Whato and welcome to the forum.
As far as travel out of the UK, I'm certainly not one for giving advice :silly: .
Is the caravan you are collecting new or used? What make and model have you plumped for?
Not that it should make any difference. Take as long as YOU need for the handover and NOT as long as the person conducting it wants to spend. Go over the entire outside and check for any damage. Check all the lockers are working as they should do.
Go over the entire inside and ensure you are happy with the fit, finish and standard.
Check that EVERY appliance is working as it should be. This means everything, all lights, oven, fridge on all settings, hot water, heating, the toilet. You get the idea.
DO NOT accept any excuses and do not be afraid to reject the van there and then if it isn't exactly as you think it should be. Do not be rushed. I would also suggest that before Sunday you get in touch with the dealer, even if it is a brand new van and ask them to have a damp report ready for when you collect as well. If the van is second hand do check all the paperwork properly and thoroughly as if you were buying a second hand car. Ensure that everything matches up as it should do.
Making the assumption that all is well with collection remember the most important thing is to enjoy your van and all your trips away in her :cheer: .