Hi Clark607, I'm also a UK owner and for the past couple of years I've been keeping am eye on the UK market. There are about 35 VXs in the UK, most good (owned by fans) but a few not so good (not owned by fans). What you really have to do is look at a few so you can get a feel for the good and bad. Get to know the features and problems of the VX so you a spot them. If you buy a bad one for 5000 rather then a good one for 3000 (and that can happen because it such a rarity and the market is all over the place because buyers and sellers really don't have a fixed idea) then rather then becoming a life long fan you will feel its an expensive millstone. Buy in haste regret in leisure.
PS the ones you have seen selling for 5000 are the ones that haven't sold for 5000 (for example the one with all the white stickers is generally consider not great having changed hands every few months). VXs do periodically appear on Ebay and occasionally on AutoTrader but you really have to bide you time and talk to the owners.