@Phaedra may beable to help regard your parking space not being designated, as I forgot how he went about it lol.
Also take a look at the Kerbocharge thread, re getting the charger lead to your car.
If your HA has given you permission, that should really be sufficient for Ohme but oh no! However surely if you accepted you may not be able to charge everyday if another vehicle was there, which is what I think Phaedra did but can’t say for sure.
Will your HA give you tempory allocated bay contract, that can be removed once Ohme is satisfied?
The other option @Struth pointed out is ask your landlord if they would apply for a £350 OLEV grant and you pay them the difference.