Vans Aircraft
There are over 2700 RVs flying around the world, thousands more under construction.
Generally, unless you have an obsessive desire to build your own airplane, I would look around for a low time used version. There are plenty of them around, usually they go for about the same price as the kit plus engine & avionics (ie the labour you get for free). Prices for RV4s and 6s (no 7s on the used market yet) range from the late 20Ks up to the 60s and beyond for really nice examples.
I'm not sure but think I read somewhere that only the RV4 was certified for aerobatics in the UK, not the 6. You could find out for sure on the PFA website
pfa which is your prime resource for homebuilding in the UK.