I used to buy/sell science fiction props a few years ago and used to have a stand at all the big TV/film memorabillia shows - NEC, Earl's Court etc.
A good few years ago at a show at the Excel centre in London there was a display of cars there, mostly reproductions (General Lee, DeLorean, K.I.T. etc) but there were 2 originals that were both owned by the same collector: an original TV series Batmobile and the original Only Fools and Horses Reliant.
He told me that he bought the Reliant after the first season of the show, when it was sold by the BBC in error
He rented it back to them for season 2 but they eventually decided to just paint up another one. The funniest thing was it was fitted with a switch to make it backfire to order