I did some flying there when it was run by pool aviation. Can't say what it's like there now, but if you want a recommendation, I can give no higher praise to EFG at biggin hill. I have been doing an IMC there and they have bent over backwards for me. I have been treated like a VIP there which makes a nice change...
Can't give too many details about PPL prices, but i will say that the instructors are excellent, and anyway as we all know, getting the cheapest PPL isn't always the best idea. If you are planning to take it further, i would look for quality training.
As i said, EFG are an excellent outfit and i wholeheartedly reccomend them.