My driving instructor was excellent. His name is 'Paul C' and he is from 1st Class Driving (http://www.1stclassdriving.co.uk/html/paulc_driving_lessons_in_deptf.html) (he covers SE1). He was absolutely perfect in all respects and will let you dictate the pace you proceed at etc. As it happens, I passed my test in less than 20 lessons. Very nice guy too!
And, no, I'm not a relation/friend of his, just a satisfied ex-pupil!
I highly recommend First Class too, I had an instructor called Chris who was brilliant. Took me a bit longer than 20 lessons to learn (very nervous driver!) but they offered block booking deals and were very flexible about lesson times etc.
I've had 4 driving lessons with Alison after seeing this, and I'm very pleased. We get on well and I'm making good progress. - And in SE1 I did qualify for the local discount. The locations are on her site
Unfortunately I only ever had his work mobile number and I don't have it anymore. He always had lots of clients when he was teaching me (2008) and had people on a waiting list as well so it may be that he isn't taking anymore for a while until others move on?