Another vote for Headcorn
I’d second patowalker’s nomination of Headcorn. It’s a bit further by road than Redhill, but it offers a variety of things going on, including aerobatics, parachuting as well as the usual light aircraft coming and going. Although it’s a grass airfield, it’s well drained and maintained, so usually keeps going through the winter when some other grass airfields have to curtail some of the flying operations.
Another advantage is that it’s relatively clear of controlled airspace, so less far to fly to the practice area for the initial part of the training. Later on when you are doing navigation exercises you won’t be bumping along the sides of the Heathrow and Gatwick controlled airspace. With the upcoming 2012 Olympic airspace restrictions I believe they will have a route to clear the restricted zone.
Several friends learned to fly at Headcorn. XX, who appears on aviation forums from time to time, learned there a few years ago. Now Mr. XX has just passed his GFT and is eagerly awaiting the arrival of his new licence.
It may be worth half a day of your time to go along and look the place over. Perhaps have a trial lesson there as well. Where ever you decide to learn, enjoy it, it’s great fun.