Secondhand RV7s are fairly rare in the UK, they do come up a few times a year though, usually advertised from £60-£75k, which is less than you could currently build one for. There are plenty for sale in the USA for less money but the cost of importation, VAT, and LAA compliance inspections would probably cancel out the difference.
The RV6 is more plentiful, cheaper, has very nearly the same performance and is a very capable aeroplane, as proven by Manuel Quieroz who flew one round the world in 2006.
Of course RV6s tend to be older (not all - some people are still finishing their builds) but most still have less than 500 flying hours.
RVs are not yet able to fly legally in IMC in the UK, and although sterling work is being done by certain peeps inside and outside the LAA, there is no date for this and there has to be a chance it may never happen.
Mogas is such a dog's breakfast at the moment with the hideous alcohol additives it's doubtful any aircraft can fly on it at present with an utterly spotless conscience - many do so anyway with no ill effects.
My advice to anyone who thinks that an RV might fit their lifestyle (what Peter calls mission profile) is fly one - they are so delightful that you may well find you will want to accept the (very few) limitations.