It is a shame but the choice of flying school / club is now limited at Biggin Hill. It is now a choice of EFT, Surrey and Kent and Allouette. I think that they all offer a good service, have been around a long time and would be good to learn at.
I learnt at Biggin, and I would say that you should choose the nearest airport to you that has the training organisation and planes that will suit you best. A few quid here or there when you are going to be spending thousands is neither there nor there, but the hours travelling to and from, up to four or five times a week (maybe more, maybe less - depends on your commitment and timescales) will soon add up to more of a pain than the landing fees.
Also, consider what type of flying you want to do after your PPL - Biggin offers you full ATC service, with good access to Thames RAdar etc. so you soon learn how to do this properly and will not then be scared of any other ATC. If you learn somewhere with air/ground, then you try to fly into a very busy controlled environment like Norwich or even Amesterdam (I dont know if you still can land there in a single but you could a few years ago - great fun apart from the expense!) you will quickly flounder and struggle. Think of it like learning to drive in central London, you will never be scared to drive anywhere afterwards!
Also, think about what planes they have that you can move onto after you get your PPL - yes train in a cheapie trainer, but you will probably want to get into something a bit nicer such as the PA28 etc. once you qualify. If the club / school you train at has a nice aircraft progression then you wont have as much hassle transitioning later, as you can probably get your familiar instructor who knows your abilities to check you out and help you up the hill!
I hope you do manage to get your PPL, and have a great time doing it and once you pass. Good luck!