Snetterton is fairly close (I've never done it myself, though) and there's Bedford Autodrome which has some events. Rockingham is sort-of on the way (well, you'd be coming a long way!) and they have spaces for the friday before the bbq - see bookatrack's website.

BaT are fine, been on events organised by them before. It's open pit lane, so make sure you know where to get some replacement tyres at the end of the day

Hugo