I intend to camp at Debden House as well. Plan is to travel down from Wirral on Friday and set up camp, have a leisurely day on Saturday to register, start the fun bit on Sunday, and then my tent and sleeping bag is there to collapse into when I finish. Naturally, my tent & car will be unattended or occupied for that period but I would expect I would just pay the normal fee for those days which I'm happy to do.