Guernsey Car - 330d
Are there any special procedures for buying a car in Guernsey and bringing it back onto mainland Britain? Car was originally bought and supplied in England, then sold to buyer in Guernsey, so all necessary UK VAT has been paid on the original purchase.
Guernsey Car - hillman
Perhaps the mods could help out with this one. I think that I've seen something before to the effect that the car wouldn't have had journeys of sufficient length to reach running temperature, brake discs being corroded, etc.
Guernsey Car - THe Growler
Not sure how on-topic this is but many moons ago I bought a VW Beetle which had been used in Jersey. It was one of the most troublesome cars I have ever had. Dropped valves, seized pistons, failed brakes to name a few.
Guernsey Car - chris_w
One thing you may need to watch out for is the fact that they may have parking tickets, congestion charges and other such penalties that are unpaid. I'm not sure how this translates back to the owner when brought back into the UK.

Having lived with a guy from Guernsey who brought his car over here, he knew he wouldn't be chased up on any kind of ticket, so he used to park his car wherever, drive around getting flashed by speed cameras, waltzing in and out of the congestion zone and never received a thing from any of them. So don't know if the car will be 'black listed' or something.

As for driving in Guernsey, the limit on the island is 35 I think, so there's a good chance the cars won't ever have seen 4th or 5th gear (or 6th!).

If you do get one from there - get a full tank of petrol - it's only 50p a litre!