Alright, ferry booking is now confirmed as well (somehow) so should be good to go in that regard.
Out of the list of suggestions (thank you) I suppose it would be McLaren > Windsor and with McLaren unfortunately not bookable, it might well be WIndsor, or possibly something closer to Oxford. Will see depending on M25 traffic on the day.
MB World, at least from the website, seems pretty empty so not sure about that one.
@Teresa I hope the club signup went through fine? Thanks for making this happen.