I've imported VW Campers from Germany before, All you need is a bill of sale, the ownership docs and temp trade plates. Once you get back to the UK you'll need to sort the headlight offset (Those stick on black wedges will do), change the fog light over to the right and get in in for MOT. I think registering it in the UK cost about £80 and they'll allocate an age related registration number. You do not need to change the clocks to MPH. I last did this about 3 years ago and was amazed how easy it was.