diff --git a/backend/src/controller/modelController.ts b/backend/src/controller/modelController.ts
index dafb6716a..08301113d 100644
--- a/backend/src/controller/modelController.ts
+++ b/backend/src/controller/modelController.ts
@@ -1,10 +1,9 @@
-import { Request, Response } from 'express';
+import { Response } from 'express';
 
 import { OpenAIGetModelRequest } from '@src/models/api/OpenAIGetModelRequest';
 import { OpenAiConfigureModelRequest } from '@src/models/api/OpenAiConfigureModelRequest';
 import { OpenAiSetModelRequest } from '@src/models/api/OpenAiSetModelRequest';
 import { MODEL_CONFIG } from '@src/models/chat';
-import { getValidOpenAIModelsList } from '@src/openai';
 
 function handleSetModel(req: OpenAiSetModelRequest, res: Response) {
 	const { model } = req.body;
@@ -37,14 +36,4 @@ function handleGetModel(req: OpenAIGetModelRequest, res: Response) {
 	res.send(req.session.chatModel);
 }
 
-function handleGetValidModels(_: Request, res: Response) {
-	const models = getValidOpenAIModelsList();
-	res.send({ models });
-}
-
-export {
-	handleSetModel,
-	handleConfigureModel,
-	handleGetModel,
-	handleGetValidModels,
-};
+export { handleSetModel, handleConfigureModel, handleGetModel };
diff --git a/backend/src/controller/startController.ts b/backend/src/controller/startController.ts
new file mode 100644
index 000000000..676c92686
--- /dev/null
+++ b/backend/src/controller/startController.ts
@@ -0,0 +1,30 @@
+import { Response } from 'express';
+
+import { GetStartRequest } from '@src/models/api/getStartRequest';
+import { LEVEL_NAMES } from '@src/models/level';
+import { getValidOpenAIModels } from '@src/openai';
+import {
+	systemRoleLevel1,
+	systemRoleLevel2,
+	systemRoleLevel3,
+} from '@src/promptTemplates';
+
+function handleStart(req: GetStartRequest, res: Response) {
+	const { level } = req.query;
+
+	const systemRoles = [
+		{ level: LEVEL_NAMES.LEVEL_1, systemRole: systemRoleLevel1 },
+		{ level: LEVEL_NAMES.LEVEL_2, systemRole: systemRoleLevel2 },
+		{ level: LEVEL_NAMES.LEVEL_3, systemRole: systemRoleLevel3 },
+	];
+
+	res.send({
+		emails: req.session.levelState[level].sentEmails,
+		chatHistory: req.session.levelState[level].chatHistory,
+		defences: req.session.levelState[level].defences,
+		availableModels: getValidOpenAIModels(),
+		systemRoles,
+	});
+}
+
+export { handleStart };
diff --git a/backend/src/controller/systemRoleController.ts b/backend/src/controller/systemRoleController.ts
deleted file mode 100644
index 432d5c6d1..000000000
--- a/backend/src/controller/systemRoleController.ts
+++ /dev/null
@@ -1,19 +0,0 @@
-import { Request, Response } from 'express';
-
-import { LEVEL_NAMES } from '@src/models/level';
-import {
-	systemRoleLevel1,
-	systemRoleLevel2,
-	systemRoleLevel3,
-} from '@src/promptTemplates';
-
-function handleGetSystemRoles(_: Request, res: Response) {
-	const systemRoles = [
-		{ level: LEVEL_NAMES.LEVEL_1, systemRole: systemRoleLevel1 },
-		{ level: LEVEL_NAMES.LEVEL_2, systemRole: systemRoleLevel2 },
-		{ level: LEVEL_NAMES.LEVEL_3, systemRole: systemRoleLevel3 },
-	];
-	res.send(systemRoles);
-}
-
-export { handleGetSystemRoles };
diff --git a/backend/src/defence.ts b/backend/src/defence.ts
index f067c5371..54a320e29 100644
--- a/backend/src/defence.ts
+++ b/backend/src/defence.ts
@@ -256,7 +256,7 @@ function transformMessage(
 		: undefined;
 
 	if (!transformedMessage) {
-		console.debug('No defences applied. Message unchanged.');
+		console.debug('No transformation applied. Message unchanged.');
 		return;
 	}
 
diff --git a/backend/src/langchain.ts b/backend/src/langchain.ts
index 8341e07dc..2e487e780 100644
--- a/backend/src/langchain.ts
+++ b/backend/src/langchain.ts
@@ -7,7 +7,7 @@ import { getDocumentVectors } from './document';
 import { CHAT_MODELS } from './models/chat';
 import { PromptEvaluationChainReply, QaChainReply } from './models/langchain';
 import { LEVEL_NAMES } from './models/level';
-import { getOpenAIKey, getValidOpenAIModelsList } from './openai';
+import { getOpenAIKey, getValidOpenAIModels } from './openai';
 import {
 	promptEvalPrompt,
 	promptEvalContextTemplate,
@@ -31,7 +31,7 @@ function makePromptTemplate(
 }
 
 function getChatModel() {
-	return getValidOpenAIModelsList().includes(CHAT_MODELS.GPT_4)
+	return getValidOpenAIModels().includes(CHAT_MODELS.GPT_4)
 		? CHAT_MODELS.GPT_4
 		: CHAT_MODELS.GPT_3_5_TURBO;
 }
diff --git a/backend/src/models/api/getStartRequest.ts b/backend/src/models/api/getStartRequest.ts
new file mode 100644
index 000000000..86d8c9dd2
--- /dev/null
+++ b/backend/src/models/api/getStartRequest.ts
@@ -0,0 +1,21 @@
+import { Request } from 'express';
+
+import { ChatMessage } from '@src/models/chatMessage';
+import { Defence } from '@src/models/defence';
+import { EmailInfo } from '@src/models/email';
+import { LEVEL_NAMES } from '@src/models/level';
+
+export type GetStartRequest = Request<
+	never,
+	{
+		emails: EmailInfo[];
+		chatHistory: ChatMessage[];
+		defences: Defence[];
+		availableModels: string[];
+		systemRoles: string[];
+	},
+	never,
+	{
+		level: LEVEL_NAMES;
+	}
+>;
diff --git a/backend/src/nonSessionRoutes.ts b/backend/src/nonSessionRoutes.ts
index cae39c5ee..2497bfa47 100644
--- a/backend/src/nonSessionRoutes.ts
+++ b/backend/src/nonSessionRoutes.ts
@@ -3,7 +3,6 @@ import { fileURLToPath } from 'node:url';
 
 import { handleGetDocuments } from './controller/documentController';
 import { handleHealthCheck } from './controller/healthController';
-import { handleGetSystemRoles } from './controller/systemRoleController';
 import { importMetaUrl } from './importMetaUtils';
 
 const router = express.Router();
@@ -16,6 +15,5 @@ router.use(
 );
 router.get('/documents', handleGetDocuments);
 router.get('/health', handleHealthCheck);
-router.get('/systemRoles', handleGetSystemRoles);
 
 export default router;
diff --git a/backend/src/openai.ts b/backend/src/openai.ts
index 553dd0883..a4a5433c2 100644
--- a/backend/src/openai.ts
+++ b/backend/src/openai.ts
@@ -439,7 +439,7 @@ async function chatGptSendMessage(
 	};
 }
 
-export const getValidOpenAIModelsList = validOpenAiModels.get;
+export const getValidOpenAIModels = validOpenAiModels.get;
 export {
 	chatGptTools,
 	chatGptSendMessage,
diff --git a/backend/src/sessionRoutes.ts b/backend/src/sessionRoutes.ts
index d9a19660e..3b8ff3240 100644
--- a/backend/src/sessionRoutes.ts
+++ b/backend/src/sessionRoutes.ts
@@ -23,10 +23,10 @@ import {
 import {
 	handleConfigureModel,
 	handleGetModel,
-	handleGetValidModels,
 	handleSetModel,
 } from './controller/modelController';
 import { handleResetProgress } from './controller/resetController';
+import { handleStart } from './controller/startController';
 import { handleTest } from './controller/testController';
 import { ChatModel, defaultChatModel } from './models/chat';
 import { LevelState, getInitialLevelStates } from './models/level';
@@ -94,6 +94,9 @@ router.use((req, _res, next) => {
 	next();
 });
 
+// handshake
+router.get('/start', handleStart);
+
 // defences
 router.get('/defence/status', handleGetDefenceStatus);
 router.post('/defence/activate', handleDefenceActivation);
@@ -112,7 +115,6 @@ router.post('/openai/addInfoToHistory', handleAddInfoToChatHistory);
 router.post('/openai/clear', handleClearChatHistory);
 
 // model configurations
-router.get('/openai/validModels', handleGetValidModels);
 router.get('/openai/model', handleGetModel);
 router.post('/openai/model', handleSetModel);
 router.post('/openai/model/configure', handleConfigureModel);
diff --git a/backend/test/unit/controller/systemRoleController.test.ts b/backend/test/unit/controller/systemRoleController.test.ts
deleted file mode 100644
index 5413eb532..000000000
--- a/backend/test/unit/controller/systemRoleController.test.ts
+++ /dev/null
@@ -1,32 +0,0 @@
-import { expect, test, jest, describe } from '@jest/globals';
-import { Request, Response } from 'express';
-
-import { handleGetSystemRoles } from '@src/controller/systemRoleController';
-import { LEVEL_NAMES } from '@src/models/level';
-import {
-	systemRoleLevel1,
-	systemRoleLevel2,
-	systemRoleLevel3,
-} from '@src/promptTemplates';
-
-describe('systemRoleController unit tests', () => {
-	function responseMock() {
-		return {
-			send: jest.fn(),
-			status: jest.fn(),
-		} as unknown as Response;
-	}
-
-	test('GIVEN a request THEN the systemRoleController should return a list of system roles', () => {
-		const expectedSystemRoles = [
-			{ level: LEVEL_NAMES.LEVEL_1, systemRole: systemRoleLevel1 },
-			{ level: LEVEL_NAMES.LEVEL_2, systemRole: systemRoleLevel2 },
-			{ level: LEVEL_NAMES.LEVEL_3, systemRole: systemRoleLevel3 },
-		];
-
-		const res = responseMock();
-		handleGetSystemRoles({} as Request, res);
-
-		expect(res.send).toHaveBeenCalledWith(expectedSystemRoles);
-	});
-});
diff --git a/backend/test/unit/langchain.ts/initialisePromptEvaluationModel.test.ts b/backend/test/unit/langchain.ts/initialisePromptEvaluationModel.test.ts
index 07fc9f8cd..055cd4547 100644
--- a/backend/test/unit/langchain.ts/initialisePromptEvaluationModel.test.ts
+++ b/backend/test/unit/langchain.ts/initialisePromptEvaluationModel.test.ts
@@ -32,7 +32,7 @@ jest.mock('@src/openai', () => {
 		jest.requireActual<typeof import('@src/openai')>('@src/openai');
 	return {
 		...originalModule,
-		getValidOpenAIModelsList: jest.fn(() => mockValidModels),
+		getValidOpenAIModels: jest.fn(() => mockValidModels),
 	};
 });
 
diff --git a/backend/test/unit/langchain.ts/initialiseQAModel.test.ts b/backend/test/unit/langchain.ts/initialiseQAModel.test.ts
index 1c27c1b47..12ad68f84 100644
--- a/backend/test/unit/langchain.ts/initialiseQAModel.test.ts
+++ b/backend/test/unit/langchain.ts/initialiseQAModel.test.ts
@@ -56,7 +56,7 @@ jest.mock('@src/openai', () => {
 		jest.requireActual<typeof import('@src/openai')>('@src/openai'); // can we remove this
 	return {
 		...originalModule,
-		getValidOpenAIModelsList: jest.fn(() => mockValidModels),
+		getValidOpenAIModels: jest.fn(() => mockValidModels),
 	};
 });
 
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 02e97530f..eade00131 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -1,14 +1,13 @@
 import { useCallback, useEffect, useRef, useState } from 'react';
 
 import DocumentViewBox from './components/DocumentViewer/DocumentViewBox';
-import HandbookOverlay from './components/HandbookOverlay/HandbookOverlay';
 import MainComponent from './components/MainComponent/MainComponent';
 import LevelsComplete from './components/Overlay/LevelsComplete';
 import MissionInformation from './components/Overlay/MissionInformation';
 import OverlayWelcome from './components/Overlay/OverlayWelcome';
 import ResetProgressOverlay from './components/Overlay/ResetProgress';
-import { LEVEL_NAMES, LevelSystemRole } from './models/level';
-import { chatService, levelService, systemRoleService } from './service';
+import { LEVEL_NAMES } from './models/level';
+import { levelService } from './service';
 
 import './App.css';
 import './Theme.css';
@@ -28,8 +27,6 @@ function App() {
 		null
 	);
 
-	const [chatModels, setChatModels] = useState<string[]>([]);
-	const [systemRoles, setSystemRoles] = useState<LevelSystemRole[]>([]);
 	const [mainComponentKey, setMainComponentKey] = useState<number>(0);
 
 	function loadIsNewUser() {
@@ -72,21 +69,6 @@ function App() {
 		setNumCompletedLevels(Math.max(numCompletedLevels, completedLevel + 1));
 	}
 
-	// fetch constants from the backend on app mount
-	async function loadBackendData() {
-		try {
-			console.log("Initializing app's backend data");
-			const [models, roles] = await Promise.all([
-				chatService.getValidModels(),
-				systemRoleService.getSystemRoles(),
-			]);
-			setChatModels(models);
-			setSystemRoles(roles);
-		} catch (err) {
-			console.log(err);
-		}
-	}
-
 	useEffect(() => {
 		// save number of completed levels to local storage
 		localStorage.setItem('numCompletedLevels', numCompletedLevels.toString());
@@ -116,11 +98,6 @@ function App() {
 		}
 	}, [isNewUser]);
 
-	// load the system constants from backend on app mount
-	useEffect(() => {
-		void loadBackendData();
-	}, []);
-
 	useEffect(() => {
 		// must re-bind event listener after changing overlay type
 		setTimeout(() => {
@@ -177,16 +154,7 @@ function App() {
 			/>
 		);
 	}
-	function openHandbook() {
-		openOverlay(
-			<HandbookOverlay
-				currentLevel={currentLevel}
-				numCompletedLevels={numCompletedLevels}
-				systemRoles={systemRoles}
-				closeOverlay={closeOverlay}
-			/>
-		);
-	}
+
 	function openInformationOverlay() {
 		openOverlay(
 			<MissionInformation
@@ -270,11 +238,9 @@ function App() {
 				key={mainComponentKey}
 				currentLevel={currentLevel}
 				numCompletedLevels={numCompletedLevels}
-				chatModels={chatModels}
 				closeOverlay={closeOverlay}
 				updateNumCompletedLevels={updateNumCompletedLevels}
 				openDocumentViewer={openDocumentViewer}
-				openHandbook={openHandbook}
 				openOverlay={openOverlay}
 				openInformationOverlay={openInformationOverlay}
 				openLevelsCompleteOverlay={openLevelsCompleteOverlay}
diff --git a/frontend/src/Defences.ts b/frontend/src/Defences.ts
index 78047cd41..a8a08213d 100644
--- a/frontend/src/Defences.ts
+++ b/frontend/src/Defences.ts
@@ -24,7 +24,7 @@ function makeDefenceConfigItem(
 	return { id, name, inputType, value: '' };
 }
 
-const DEFENCES_SHOWN_LEVEL3: Defence[] = [
+const DEFAULT_DEFENCES: Defence[] = [
 	makeDefence(
 		DEFENCE_ID.CHARACTER_LIMIT,
 		'Character Limit',
@@ -83,10 +83,6 @@ const DEFENCES_SHOWN_LEVEL3: Defence[] = [
 		'Use an LLM to evaluate the user input for malicious content and prompt injection attacks.',
 		[makeDefenceConfigItem('PROMPT', 'prompt', 'text')]
 	),
-];
-
-const ALL_DEFENCES: Defence[] = [
-	...DEFENCES_SHOWN_LEVEL3,
 	makeDefence(
 		DEFENCE_ID.SYSTEM_ROLE,
 		'System Role',
@@ -101,6 +97,8 @@ const ALL_DEFENCES: Defence[] = [
 	),
 ];
 
+const DEFENCES_HIDDEN_LEVEL3_IDS = [DEFENCE_ID.SYSTEM_ROLE, DEFENCE_ID.QA_LLM];
+
 const MODEL_DEFENCES = [
 	DEFENCE_ID.PROMPT_EVALUATION_LLM,
 	DEFENCE_ID.QA_LLM,
@@ -114,8 +112,8 @@ const PROMPT_ENCLOSURE_DEFENCES = [
 ];
 
 export {
-	DEFENCES_SHOWN_LEVEL3,
-	ALL_DEFENCES,
+	DEFAULT_DEFENCES,
 	MODEL_DEFENCES,
 	PROMPT_ENCLOSURE_DEFENCES,
+	DEFENCES_HIDDEN_LEVEL3_IDS,
 };
diff --git a/frontend/src/components/ChatBox/ChatBox.tsx b/frontend/src/components/ChatBox/ChatBox.tsx
index 25fc32f13..8057cf60f 100644
--- a/frontend/src/components/ChatBox/ChatBox.tsx
+++ b/frontend/src/components/ChatBox/ChatBox.tsx
@@ -1,6 +1,6 @@
 import { useEffect, useState } from 'react';
 
-import { ALL_DEFENCES } from '@src/Defences';
+import { DEFAULT_DEFENCES } from '@src/Defences';
 import ExportPDFLink from '@src/components/ExportChat/ExportPDFLink';
 import '@src/components/ThemedButtons/ChatButton.css';
 import LoadingButton from '@src/components/ThemedButtons/LoadingButton';
@@ -111,7 +111,7 @@ function ChatBox({
 		}
 		response.defenceReport.alertedDefences.forEach((triggeredDefence) => {
 			// get user-friendly defence name
-			const defenceName = ALL_DEFENCES.find((defence) => {
+			const defenceName = DEFAULT_DEFENCES.find((defence) => {
 				return defence.id === triggeredDefence;
 			})?.name.toLowerCase();
 			if (defenceName) {
@@ -131,7 +131,7 @@ function ChatBox({
 		// add triggered defences to the chat
 		response.defenceReport.triggeredDefences.forEach((triggeredDefence) => {
 			// get user-friendly defence name
-			const defenceName = ALL_DEFENCES.find((defence) => {
+			const defenceName = DEFAULT_DEFENCES.find((defence) => {
 				return defence.id === triggeredDefence;
 			})?.name.toLowerCase();
 			if (defenceName) {
diff --git a/frontend/src/components/ControlPanel/ControlPanel.tsx b/frontend/src/components/ControlPanel/ControlPanel.tsx
index d1c9ef608..3a165192d 100644
--- a/frontend/src/components/ControlPanel/ControlPanel.tsx
+++ b/frontend/src/components/ControlPanel/ControlPanel.tsx
@@ -1,4 +1,4 @@
-import { MODEL_DEFENCES } from '@src/Defences';
+import { DEFENCES_HIDDEN_LEVEL3_IDS, MODEL_DEFENCES } from '@src/Defences';
 import DefenceBox from '@src/components/DefenceBox/DefenceBox';
 import DocumentViewButton from '@src/components/DocumentViewer/DocumentViewButton';
 import ModelBox from '@src/components/ModelBox/ModelBox';
@@ -29,12 +29,21 @@ function ControlPanel({
 	openDocumentViewer: () => void;
 	addInfoMessage: (message: string) => void;
 }) {
-	const configurableDefences = defences.filter(
-		(defence) => !MODEL_DEFENCES.some((id) => id === defence.id)
+	const configurableDefences =
+		currentLevel === LEVEL_NAMES.SANDBOX
+			? defences
+			: currentLevel === LEVEL_NAMES.LEVEL_3
+			? defences.filter(
+					(defence) => !DEFENCES_HIDDEN_LEVEL3_IDS.includes(defence.id)
+			  )
+			: [];
+
+	const nonModelDefences = configurableDefences.filter(
+		(defence) => !MODEL_DEFENCES.includes(defence.id)
 	);
 
-	const modelDefences = defences.filter((defence) =>
-		MODEL_DEFENCES.some((id) => id === defence.id)
+	const modelDefences = configurableDefences.filter((defence) =>
+		MODEL_DEFENCES.includes(defence.id)
 	);
 
 	// only allow configuration in sandbox
@@ -53,7 +62,7 @@ function ControlPanel({
 						</summary>
 						<DefenceBox
 							currentLevel={currentLevel}
-							defences={configurableDefences}
+							defences={nonModelDefences}
 							showConfigurations={showConfigurations}
 							resetDefenceConfiguration={resetDefenceConfiguration}
 							toggleDefence={toggleDefence}
diff --git a/frontend/src/components/LevelSelectionBox/LevelSelectionBox.css b/frontend/src/components/LevelSelectionBox/LevelSelectionBox.css
index c61f7e95f..53551a3a1 100644
--- a/frontend/src/components/LevelSelectionBox/LevelSelectionBox.css
+++ b/frontend/src/components/LevelSelectionBox/LevelSelectionBox.css
@@ -21,8 +21,8 @@
 
 .level-button.selected {
 	background-color: var(--level-button-background-colour-selected);
-	cursor: default;
 	color: var(--level-button-colour);
+	cursor: default;
 }
 
 .level-button.disabled {
diff --git a/frontend/src/components/MainComponent/MainComponent.tsx b/frontend/src/components/MainComponent/MainComponent.tsx
index f3442ee05..3390ae6aa 100644
--- a/frontend/src/components/MainComponent/MainComponent.tsx
+++ b/frontend/src/components/MainComponent/MainComponent.tsx
@@ -1,17 +1,18 @@
-import { useEffect, useState } from 'react';
+import { useEffect, useRef, useState } from 'react';
 
-import { ALL_DEFENCES, DEFENCES_SHOWN_LEVEL3 } from '@src/Defences';
+import { DEFAULT_DEFENCES } from '@src/Defences';
+import HandbookOverlay from '@src/components/HandbookOverlay/HandbookOverlay';
 import LevelMissionInfoBanner from '@src/components/LevelMissionInfoBanner/LevelMissionInfoBanner';
 import ResetLevelOverlay from '@src/components/Overlay/ResetLevel';
 import { ChatMessage } from '@src/models/chat';
 import { DEFENCE_ID, DefenceConfigItem, Defence } from '@src/models/defence';
 import { EmailInfo } from '@src/models/email';
-import { LEVEL_NAMES } from '@src/models/level';
+import { LEVEL_NAMES, LevelSystemRole } from '@src/models/level';
 import {
 	chatService,
 	defenceService,
 	emailService,
-	healthService,
+	startService,
 } from '@src/service';
 
 import MainBody from './MainBody';
@@ -21,13 +22,11 @@ import MainHeader from './MainHeader';
 import './MainComponent.css';
 
 function MainComponent({
-	chatModels,
 	currentLevel,
 	numCompletedLevels,
 	closeOverlay,
 	updateNumCompletedLevels,
 	openDocumentViewer,
-	openHandbook,
 	openInformationOverlay,
 	openLevelsCompleteOverlay,
 	openOverlay,
@@ -35,13 +34,11 @@ function MainComponent({
 	openWelcomeOverlay,
 	setCurrentLevel,
 }: {
-	chatModels: string[];
 	currentLevel: LEVEL_NAMES;
 	numCompletedLevels: number;
 	closeOverlay: () => void;
 	updateNumCompletedLevels: (level: number) => void;
 	openDocumentViewer: () => void;
-	openHandbook: () => void;
 	openInformationOverlay: () => void;
 	openLevelsCompleteOverlay: () => void;
 	openOverlay: (overlayComponent: JSX.Element) => void;
@@ -50,27 +47,53 @@ function MainComponent({
 	setCurrentLevel: (newLevel: LEVEL_NAMES) => void;
 }) {
 	const [MainBodyKey, setMainBodyKey] = useState<number>(0);
-	const [defencesToShow, setDefencesToShow] = useState<Defence[]>(ALL_DEFENCES);
-	const [emails, setEmails] = useState<EmailInfo[]>([]);
+	const [defences, setDefences] = useState<Defence[]>(DEFAULT_DEFENCES);
 	const [messages, setMessages] = useState<ChatMessage[]>([]);
+	const [emails, setEmails] = useState<EmailInfo[]>([]);
+	const [chatModels, setChatModels] = useState<string[]>([]);
+	const [systemRoles, setSystemRoles] = useState<LevelSystemRole[]>([]);
+
+	const isFirstRender = useRef(true);
 
-	// called on mount
+	// facilitate refresh / first render
 	useEffect(() => {
-		// perform backend health check
-		healthService.healthCheck().catch(() => {
-			// addErrorMessage('Failed to reach the server. Please try again later.');
+		console.log(
+			'Loading initial backend data plus data for level',
+			currentLevel
+		);
+		void loadBackendData();
+	}, []);
+
+	// facilitate level change
+	useEffect(() => {
+		console.log(
+			'useEffect currentLevel. isFirstRender.current:',
+			isFirstRender.current
+		);
+		if (!isFirstRender.current) {
+			console.log('Loading backend data for level', currentLevel);
+			void setNewLevel(currentLevel);
+		}
+		isFirstRender.current = false;
+	}, [currentLevel]);
+
+	async function loadBackendData() {
+		try {
+			const { availableModels, defences, emails, history, systemRoles } =
+				await startService.start(currentLevel);
+			setChatModels(availableModels);
+			setSystemRoles(systemRoles);
+			processBackendLevelData(currentLevel, emails, history, defences);
+		} catch (err) {
+			console.warn(err);
 			setMessages([
 				{
 					message: 'Failed to reach the server. Please try again later.',
 					type: 'ERROR_MSG',
 				},
 			]);
-		});
-	}, []);
-
-	useEffect(() => {
-		void setNewLevel(currentLevel);
-	}, [currentLevel]);
+		}
+	}
 
 	function openResetLevelOverlay() {
 		openOverlay(
@@ -85,6 +108,17 @@ function MainComponent({
 		);
 	}
 
+	function openHandbook() {
+		openOverlay(
+			<HandbookOverlay
+				currentLevel={currentLevel}
+				numCompletedLevels={numCompletedLevels}
+				systemRoles={systemRoles}
+				closeOverlay={closeOverlay}
+			/>
+		);
+	}
+
 	// methods to modify messages
 	function addChatMessage(message: ChatMessage) {
 		setMessages((messages: ChatMessage[]) => [...messages, message]);
@@ -116,41 +150,26 @@ function MainComponent({
 
 	// for going switching level without clearing progress
 	async function setNewLevel(newLevel: LEVEL_NAMES) {
-		// get emails for new level from the backend
-		setEmails(await emailService.getSentEmails(newLevel));
+		const emails = await emailService.getSentEmails(newLevel);
+		const chatHistory = await chatService.getChatHistory(newLevel);
+		const defences = await defenceService.getDefences(newLevel);
+		processBackendLevelData(newLevel, emails, chatHistory, defences);
+	}
 
-		// get chat history for new level from the backend
-		const retrievedMessages = await chatService.getChatHistory(newLevel);
+	function processBackendLevelData(
+		level: LEVEL_NAMES,
+		emails: EmailInfo[],
+		chatHistory: ChatMessage[],
+		defences: Defence[]
+	) {
+		setEmails(emails);
 
 		// add welcome message for levels only
-		newLevel !== LEVEL_NAMES.SANDBOX
-			? setMessagesWithWelcome(retrievedMessages)
-			: setMessages(retrievedMessages);
+		level !== LEVEL_NAMES.SANDBOX
+			? setMessagesWithWelcome(chatHistory)
+			: setMessages(chatHistory);
 
-		const defences =
-			newLevel === LEVEL_NAMES.LEVEL_3 ? DEFENCES_SHOWN_LEVEL3 : ALL_DEFENCES;
-		// fetch defences from backend
-		const remoteDefences = await defenceService.getDefences(newLevel);
-		defences.map((localDefence) => {
-			const matchingRemoteDefence = remoteDefences.find((remoteDefence) => {
-				return localDefence.id === remoteDefence.id;
-			});
-			if (matchingRemoteDefence) {
-				localDefence.isActive = matchingRemoteDefence.isActive;
-				// set each config value
-				matchingRemoteDefence.config.forEach((configEntry) => {
-					// get the matching config in the local defence
-					const matchingConfig = localDefence.config.find((config) => {
-						return config.id === configEntry.id;
-					});
-					if (matchingConfig) {
-						matchingConfig.value = configEntry.value;
-					}
-				});
-			}
-			return localDefence;
-		});
-		setDefencesToShow(defences);
+		setDefences(defences);
 		setMainBodyKey(MainBodyKey + 1);
 	}
 
@@ -182,7 +201,7 @@ function MainComponent({
 		);
 		addConfigUpdateToChat(defenceId, 'reset');
 		// update state
-		const newDefences = defencesToShow.map((defence) => {
+		const newDefences = defences.map((defence) => {
 			if (defence.id === defenceId) {
 				defence.config.forEach((config) => {
 					if (config.id === configId) {
@@ -192,7 +211,7 @@ function MainComponent({
 			}
 			return defence;
 		});
-		setDefencesToShow(newDefences);
+		setDefences(newDefences);
 	}
 
 	async function setDefenceToggle(defence: Defence) {
@@ -202,7 +221,7 @@ function MainComponent({
 			currentLevel
 		);
 
-		const newDefenceDetails = defencesToShow.map((defenceDetail) => {
+		const newDefenceDetails = defences.map((defenceDetail) => {
 			if (defenceDetail.id === defence.id) {
 				defenceDetail.isActive = !defence.isActive;
 				const action = defenceDetail.isActive ? 'activated' : 'deactivated';
@@ -212,7 +231,7 @@ function MainComponent({
 			return defenceDetail;
 		});
 
-		setDefencesToShow(newDefenceDetails);
+		setDefences(newDefenceDetails);
 	}
 
 	async function setDefenceConfiguration(
@@ -227,13 +246,13 @@ function MainComponent({
 		if (success) {
 			addConfigUpdateToChat(defenceId, 'updated');
 			// update state
-			const newDefences = defencesToShow.map((defence) => {
+			const newDefences = defences.map((defence) => {
 				if (defence.id === defenceId) {
 					defence.config = config;
 				}
 				return defence;
 			});
-			setDefencesToShow(newDefences);
+			setDefences(newDefences);
 		}
 		return success;
 	}
@@ -286,7 +305,7 @@ function MainComponent({
 			<MainBody
 				key={MainBodyKey}
 				currentLevel={currentLevel}
-				defences={defencesToShow}
+				defences={defences}
 				chatModels={chatModels}
 				emails={emails}
 				messages={messages}
diff --git a/frontend/src/models/combined.ts b/frontend/src/models/combined.ts
new file mode 100644
index 000000000..b99fa0c61
--- /dev/null
+++ b/frontend/src/models/combined.ts
@@ -0,0 +1,14 @@
+import { ChatMessageDTO } from './chat';
+import { DefenceDTO } from './defence';
+import { EmailInfo } from './email';
+import { LevelSystemRole } from './level';
+
+type StartReponse = {
+	emails: EmailInfo[];
+	chatHistory: ChatMessageDTO[];
+	defences: DefenceDTO[];
+	availableModels: string[];
+	systemRoles: LevelSystemRole[];
+};
+
+export type { StartReponse };
diff --git a/frontend/src/models/defence.ts b/frontend/src/models/defence.ts
index dc95131f4..115035886 100644
--- a/frontend/src/models/defence.ts
+++ b/frontend/src/models/defence.ts
@@ -34,6 +34,17 @@ type Defence = {
 	isActive: boolean;
 };
 
+type DefenceDTO = {
+	id: DEFENCE_ID;
+	config: DefenceConfigItemDTO[];
+	isActive: boolean;
+};
+
+type DefenceConfigItemDTO = {
+	id: DEFENCE_CONFIG_ITEM_ID;
+	value: string;
+};
+
 type DefenceResetResponse = {
 	id: string;
 	value: string;
@@ -45,4 +56,6 @@ export type {
 	DEFENCE_CONFIG_ITEM_ID,
 	DefenceConfigItem,
 	Defence,
+	DefenceDTO,
+	DefenceConfigItemDTO,
 };
diff --git a/frontend/src/service/chatService.ts b/frontend/src/service/chatService.ts
index 22b66ea61..9bd7b749f 100644
--- a/frontend/src/service/chatService.ts
+++ b/frontend/src/service/chatService.ts
@@ -66,6 +66,10 @@ async function getChatHistory(level: number): Promise<ChatMessage[]> {
 	});
 	const chatMessageDTOs = (await response.json()) as ChatMessageDTO[];
 
+	return getChatMessagesFromDTOResponse(chatMessageDTOs);
+}
+
+function getChatMessagesFromDTOResponse(chatMessageDTOs: ChatMessageDTO[]) {
 	return chatMessageDTOs
 		.filter(chatMessageDTOIsConvertible)
 		.map(makeChatMessageFromDTO);
@@ -97,14 +101,6 @@ async function getGptModel(): Promise<ChatModel> {
 	return (await response.json()) as ChatModel;
 }
 
-async function getValidModels(): Promise<string[]> {
-	const response = await sendRequest(`${PATH}validModels`, { method: 'GET' });
-	const data = (await response.json()) as {
-		models: string[];
-	};
-	return data.models;
-}
-
 async function addInfoMessageToChatHistory(
 	message: string,
 	chatMessageType: CHAT_MESSAGE_TYPE,
@@ -128,7 +124,7 @@ export {
 	configureGptModel,
 	getGptModel,
 	setGptModel,
-	getValidModels,
 	getChatHistory,
 	addInfoMessageToChatHistory,
+	getChatMessagesFromDTOResponse,
 };
diff --git a/frontend/src/service/defenceService.ts b/frontend/src/service/defenceService.ts
index 3edf83d4f..460a8a8f6 100644
--- a/frontend/src/service/defenceService.ts
+++ b/frontend/src/service/defenceService.ts
@@ -1,8 +1,9 @@
+import { DEFAULT_DEFENCES } from '@src/Defences';
 import {
 	DEFENCE_ID,
 	DefenceConfigItem,
-	Defence,
 	DefenceResetResponse,
+	DefenceDTO,
 } from '@src/models/defence';
 
 import { sendRequest } from './backendService';
@@ -13,7 +14,30 @@ async function getDefences(level: number) {
 	const response = await sendRequest(`${PATH}status?level=${level}`, {
 		method: 'GET',
 	});
-	return (await response.json()) as Defence[];
+	const defenceDTOs = (await response.json()) as DefenceDTO[];
+	return getDefencesFromDTOs(defenceDTOs);
+}
+
+function getDefencesFromDTOs(defenceDTOs: DefenceDTO[]) {
+	return DEFAULT_DEFENCES.map((defence) => {
+		const defenceDTO = defenceDTOs.find(
+			(defenceDTO) => defence.id === defenceDTO.id
+		);
+		return defenceDTO
+			? {
+					...defence,
+					isActive: defenceDTO.isActive,
+					config: defence.config.map((config) => {
+						const matchingConfigItemDTO = defenceDTO.config.find(
+							(configItemDTO) => config.id === configItemDTO.id
+						);
+						return matchingConfigItemDTO
+							? { ...config, value: matchingConfigItemDTO.value }
+							: config;
+					}),
+			  }
+			: defence;
+	});
 }
 
 async function toggleDefence(
@@ -103,4 +127,5 @@ export {
 	configureDefence,
 	resetDefenceConfig,
 	validateDefence,
+	getDefencesFromDTOs,
 };
diff --git a/frontend/src/service/healthService.ts b/frontend/src/service/healthService.ts
deleted file mode 100644
index 52b37e713..000000000
--- a/frontend/src/service/healthService.ts
+++ /dev/null
@@ -1,10 +0,0 @@
-import { sendRequest } from './backendService';
-
-const PATH = 'health/';
-
-async function healthCheck() {
-	const response = await sendRequest(PATH, { method: 'GET' });
-	return response.status === 200;
-}
-
-export { healthCheck };
diff --git a/frontend/src/service/index.ts b/frontend/src/service/index.ts
index 5d611c740..eb03f0626 100644
--- a/frontend/src/service/index.ts
+++ b/frontend/src/service/index.ts
@@ -2,16 +2,14 @@ import * as chatService from './chatService';
 import * as defenceService from './defenceService';
 import * as documentService from './documentService';
 import * as emailService from './emailService';
-import * as healthService from './healthService';
 import * as levelService from './levelService';
-import * as systemRoleService from './systemRoleService';
+import * as startService from './startService';
 
 export {
 	chatService,
 	defenceService,
 	documentService,
 	emailService,
-	healthService,
 	levelService,
-	systemRoleService,
+	startService,
 };
diff --git a/frontend/src/service/startService.ts b/frontend/src/service/startService.ts
new file mode 100644
index 000000000..d1315dbfc
--- /dev/null
+++ b/frontend/src/service/startService.ts
@@ -0,0 +1,25 @@
+import { StartReponse } from '@src/models/combined';
+
+import { sendRequest } from './backendService';
+import { getChatMessagesFromDTOResponse } from './chatService';
+import { getDefencesFromDTOs } from './defenceService';
+
+const PATH = 'start/';
+
+async function start(level: number) {
+	const response = await sendRequest(`${PATH}?level=${level}`, {
+		method: 'GET',
+	});
+	const { availableModels, defences, emails, chatHistory, systemRoles } =
+		(await response.json()) as StartReponse;
+
+	return {
+		emails,
+		history: getChatMessagesFromDTOResponse(chatHistory),
+		defences: getDefencesFromDTOs(defences),
+		availableModels,
+		systemRoles,
+	};
+}
+
+export { start };
diff --git a/frontend/src/service/systemRoleService.ts b/frontend/src/service/systemRoleService.ts
deleted file mode 100644
index 4d501b397..000000000
--- a/frontend/src/service/systemRoleService.ts
+++ /dev/null
@@ -1,13 +0,0 @@
-import { LevelSystemRole } from '@src/models/level';
-
-import { sendRequest } from './backendService';
-
-const PATH = 'systemRoles/';
-
-// get the system roles for all levels
-async function getSystemRoles(): Promise<LevelSystemRole[]> {
-	const response = await sendRequest(PATH, { method: 'GET' });
-	return (await response.json()) as LevelSystemRole[];
-}
-
-export { getSystemRoles };