Have a look here for some of your answers:
http://www.pprune.org/private-flying...train-ppl.html
http://www.pprune.org/private-flying...-scotland.html
Cost wise, you are recommended not to pay up front, as schools have a habit of going bust, taking your money with them, no matter how good they look. Some of the "all in" packages offered also only include the bare minimum and don't include exams or landing fees at other air fields. If you do an intensive course, you learn quickly and you have a natural aptitude, you might make in the in the minimum time (45 hours flying time for PPL). Most people don't, and so have to continue to pay the additional cost of lessons. Cost is probably around £7000 - but there are a huge number of variables.
Location - you have the joys of the Olympics which is restricting much of London's airspace which will make things harder this summer. There are lots of training schools around from what I hear, but being up north, I can't recommend any. Google is your friend. Pick a place you can get to easily, as with the UK weather, and planes going "tech", there will be lots of days you get to the airport and can't fly. Also try and get trial lessons at a few, to see which suits you. I suggest selecting a few, then asking more specific questions here.
A PPL with a SEP rating, allows you to fly, not for profit, a single-
piston-engined, non-
turbocharged, fixed-pitch
propeller, fixed
tricycle gear, non-
pressurised land aeroplanes (with a few exceptions), during the day, in good visibility and within sight of the ground (in UK). There are few of these aircraft which have more than 4 seats. See
Pilot licensing in the United Kingdom - Wikipedia, the free encyclopedia for a summary of different licence options.
If you get a UK PPL, you can fly a UK registered plane in any country in the world pretty much.
Good luck - happy future flying!