M11/M25 that would put you near Stapleford if I remember correctly, I am fairly sure there is a flying school there but do a search on the net.
The flying school at Stapleford is
Stapleford Flight Centre and is where I did my PPL.
I started having lessons at 14, and had my licence for my 17th birthday. Did all of my exams whilst completing my A-Levels and found it fine.
Best thing to do is to have a look around at the schools you are interested in. Good luck wherever you decide to train!