I've bought cable from Futureshop online and they were good for price
& service.
A tech guy called Adam was a great help.

Also found Richer Sounds great but mainly because there's a shop down
the road. Only limited though as all their good cables are Cambridge
Audio.

Found SevenOaks really helpful but V V expensive.

Projector Point has great website if you have a projector + staff are
dead friendly and the techies are more than willing to discuss any
queries you have.

Based in E. Midlands
Hope this helps