Octopus Power-Ups automation help

[cliver1956]

Happy New Year everyone and huge thanks to @BottlecapDave and all involved in the development of this fantastic integration.
As the title suggests I'm trying to create automation to set up my system, solar + battery + EV charger, to make best use of the Power-Ups by charging the house battery, importing all consumption from the grid and charging the EV using the Zappi integration.
I am already doing similar for the cheap rate periods on Intelligent go using the "intelligent despatching" entity, which seems to be working fine.
As I understand it (feel free to correct me if I'm wrong) there is currently no API data entity that identifies when a Power-up starts and ends.
So I am creating a calendar entry for each power-up when I get the email and using that to trigger one automation to set things up when it starts and another to reset back to 'normal' when it ends.
My question is how best to handle the EV charger set up.
Under normal circumstances Intelligent Smart Charge is On so that when I plug in I just set my charge to add (Intelligent charge target) and Target Ready By Time for Octopus to work out a charge schedule automatically. The problem arises when I plug in early in anticipation of a power-up. In this case Octopus will create a schedule and possibly start a charge before the Power-up, which I don't really want.
If I turn off Intelligent Smart Charge (manually) it prevents the schedule being created and therefore any automatic charging taking place. If I then try to switch on Intelligent Bump Charge in the Power-up automation it fails to turn on unless I turn on Intelligent Smart Charge first, which enable Octopus to start controlling the charger and possibly interfering with my desired to charge for the full period of the Power-up.
If I turn off Intelligent Smart Charge, and leave it off until the end of the upcoming Power-up, can I use the entity Octopus Bump Charge to control the charger during the Power-up?
Or should I use the Zappi entity Home Charger Charge Mode?
I'm a little confused as to the relationships between the entities.
Thanks for reading and any pointers appreciated.