Berkshire bodyshop in Newbury is one of the better ones in this particular area, i have seen examples of thier work and was surprised by the quality workmanship.
Price aint too bad either, but it all depends on exactly what paint you are having, obviously matallic and pearls are a lot more expensive.

Virtually next door to berkshire bodyshop is a company the specialises in car wiring, you could ask them about the rear lights, i know they did someones orion that i know, i dont know the name of the company, i can find out tomorrow for you..

Might just have to bite the bullet, and ask the garage where the MOT is done, to fix the rear brakes for you.

If your mechanic has changed all the parts, did you see this happen?