I can personally recomend Bedford autodrome (Jonathon Palmers place). Huge track with loads of different permutations, great marshalling, really good surface, top facilities, although the onsite (Super only) unleaded petrol is a tad on the pricey side. There is also usually an instructor (or 2) on hand who will jump in the car with you and give you really good advice on your lines/braking points after spending 1 or 2 laps as a quiet observer.
If you dont want to take your own car but get some good track experience I can also recomend Thruxton. Ok the track isn't the most exciting but the instructors are very good teaching you proper lines (cornering lines of track as you are no doubt aware are extremely different to safe road lines) and you will, at the end of the day, get to drive 5 laps in the supercar of your choice with an instructor alongside you (Lambo Murchiwhatnot in Pearl white is the current top choice
, but you can drive a prancing pony if you desire).
both places have websites, but blasted if I can remember them right now...