There is the CC's Rookesbury Park site. I think it is also open to non members? It is certainly geared up for the ferry traffic.
Travelling a little further but on route you will be taking if going home is the CC's Mornhill at Winchester, just off the M3; it certainly takes non members and a phone call will determine how they cope with evening arrivals.
The C&CC's Chichester site is quite near at Nutbourne; even from there you could route homeward up the A3M to the A3 > M25
Just after you come off the Ferry at Caen there is a garage they don't take Credit Cards but do take Debit Cards. I use it on the way back every time we go that way.
A day of all things motorhome and campervan. The show is held both in the main indoor arena and across the grounds. Catering, hot drinks and food options are available. Easy access to the site and free parking included. Win one of five pairs of day tickets