Why would EVs be expecting to trickle charge overnight? Even on a fairly small car I only get about 7 miles of charge per hour on a three pin socket but I could charge a lot more quickly on a public charger on the way there. Don't get me wrong if it was available and cheap I would but it needn't be essential in fact with a huge by comparison battery on board and EV would be very good off grid for some time.OK, I'll rewrite my letter and change it to a C&MHC greenfield CL site in Wales.
My point is:
I have yet to see my first EV charging point on a UK campsite (Seen a couple in Germany).
It would appear most UK campsites are not yet ready for the day when the majority of vehicles arriving are EV's and expect to be able to trickle charge overnight.
I'm only aware of one UK site where electricity is metered (Shingle Hall Farm near Rye) although no doubt there will be others.