I would say 9k is well overpriced. I have seen a couple of Mk 3's (high mileage) for less than that. If you're willing to spend upto 9k on a P38, you will find some well looked after examples for a lot less.
LPG divides opinion, some say it runs too hot for these engines. But if I had my time again I'd take the chance and pay 56p a litre rather than £1.08. Don't do enough mileage to convert mine.