I think, if it were me, I would be onto Kia UK with a strong worded complaint about the croc of shit dealer or person and that my next move if it wernt sorted, I would have no hesitation going to the Ombudsman, as the car is not fit for pupose for the UK as is!
Kia states the EV3 supports AC charging with a maximum capacity of 11kW, which includes 3.6kW, 7.4kW. If however, they said a minimum of 11kW, that would of course be a different story, but they don’t.
Can’t say I was shock when you said Arnold Clarke.