Yeah there is a place by Bristol Dogs Home, it is underneath the Railway Bridge, Awesome Imports. I went there last week and bought a pair of rear lights, spoke to a couple of the guys there, they claim to have most parts on the shelf plus one of their fitters has just broken 2 pulsars and has plenty of spares. They seem quite reasonable, i paid £30 for 2 rear light clusters with bulb holders.
Rgs Pete