Have a look around, ask a few questions to resident instructors or PPL's milling around and see what one works out best in terms of location, and your inner sense.
I fly from Panshanger, near Welwyn Garden City, it is has a nice informal club atmosphere, the training is thorough, it has a fairly long grass runway and a number of PA28 low wing aircraft. When I was looking around for my PPL, one of their engineers took the trouble to take me out to an aircraft and explain a few things to me. I liked that, and immediately booked up my first lesson in the following week.
You also have to think about what you want to do when you have passed. E.g. is the location suitable for your kind of touring; do they have other planes (e.g. complex, aerobatic or tail wheel aircraft) you might fancy extending your license too; do they have night training or some kind of instrument training facilities; is the food any good etc...