It sounds like you are taking the ferry from Portsmouth, which is due in at 2130. I am taking that ferry at the end of May and intend dropping into Les Pommiers (very close to the Port). I have done this before and if my memory serves me, it is open until 2300 and they expect to take custom from the late ferry. It is not the best site in the area but it is more than adequate, with easy access, large pitches, wide site roads and easy to find in the dark. It is a good night halt. Try and pitch down near the canal where it is quiet.