I had mine done here
http://www.westlondonmotorcycletraining.com/
More a privateer type job. Not a big training school. Slightly cheaper than the big centres. Usually meets ppl at the Suzuki dealership in Feltham, which is near Heathrow.
Instructor is a bit lacronic. Like bikers, doesn't hold back on profanities. But nice enough. Training's done around Feltham and the test centre's in Pinner. I think in general a good place. Not too crowded. Lots of learner vehicles, cars and bikes. Not a bad place to start.
Just make sure to get good riding gear, helmets and all. Would have passed the first time, except that I wasn't wearing the right gear, and it was a freezing April like this one, and the examiner didn't see my mirror checks cos i was shivering too much to turn my head properly! The side roads are quiet, so good for u-turns and such.
Didn't bother with any training manuals i have to say for the theory test. I just went to one of those free internet sites and made sure i got every question posted right. THere's only so few. If you can pass all those 100%, about 2/3 of the actual questions will come from there. And that should be enough to pass. as for the Hazard awareness bit, came as a shock since i didn't actually read that there is such a segment. but like all things, its about safety. Just think about safety at all times. Same with the hazards. Anything that could remotely get in your way, just click away.