[StuartEV]

I would argue that the Zoe charger isn't being fussy, it's doing something that all chargers should really do as a matter of course. Checking Zs before starting to charge makes a great deal of sense, especially given the state of a fair number of UK electrical installations. Being confident that Zs is low enough to ensure that an RCD trips rapidly in the event of a leakage fault is very definitely a good thing to do, in my view.

Yes its is a good idea, but to be fair to the others it is far more important for a zoe than most. Most other OBCs I have seen bereakdowns/schematics for (tesla, nissan, hyundai, kia) all have galvanic isolation between the AC and high voltage DC bus (they are all basically just scaled up SMPS with water cooling to keep the size down).

The fast AC charging zoes don't have any isolation here. They just a have rectifier feeding the inverter (running in the 'regen' direction ) via the motor stator windings (acting as inductors for a giant boost converter). That's a hell of a lot more cable and components that could lead to an isolation fault than hence the higher need to take precautions.