Hi Pete
Go to their web site
www.gdsf.co.uk
Go onto bookings then faq's
Have a look at what they do and dont allow on the caravan site before you book. Boy are they strict ! I tried a few years ago with a real Land Rover 90 defender County, ie with side windows (not a home made one) as the tow car and was refused.
Phone before you go.
Regards
Ray