6k is way too much for something on the register, and i'd say finding out if it was cat c or d will make a difference to the price as well.

do a proper hpi and see what it says if your seriously interested in it.

price wont matter too much if you buy on condition and plan to keep it for a while, when it comes to sell it thats whn you might take a hit if you pay over the odds for it now, being on the list will put a lot of people off