diff --git a/api.planx.uk/modules/send/utils/exportZip.test.ts b/api.planx.uk/modules/send/utils/exportZip.test.ts
index 48fe1ce7dd..cce3cc64ca 100644
--- a/api.planx.uk/modules/send/utils/exportZip.test.ts
+++ b/api.planx.uk/modules/send/utils/exportZip.test.ts
@@ -7,6 +7,7 @@ jest.mock("fs", () => ({
   existsSync: () => true,
   unlinkSync: () => undefined,
   createWriteStream: () => undefined,
+  writeFileSync: () => undefined,
   rmSync: () => undefined,
 }));
 
diff --git a/api.planx.uk/modules/send/utils/exportZip.ts b/api.planx.uk/modules/send/utils/exportZip.ts
index 3cfec11cca..379f1bf9ec 100644
--- a/api.planx.uk/modules/send/utils/exportZip.ts
+++ b/api.planx.uk/modules/send/utils/exportZip.ts
@@ -197,7 +197,9 @@ export class ExportZip {
       throw new Error("file not found");
     }
     const filePath = path.join(this.tmpDir, name);
-    this.zip.addFile(filePath, body as Buffer);
+    fs.writeFileSync(filePath, body as Buffer);
+    this.zip.addLocalFile(filePath);
+    fs.unlinkSync(filePath);
   }
 
   toBuffer(): Buffer {