They have a very dubious reputation and should have been closed down several years ago.
Originally Posted by Ian Grant
There is another, about 10 miles south of Central London in Windmill Road, Croydon. 'Mr Cad' ('Cad' stands for Camera Audio Discount) He is another to be wary of, - very wary! His used equipment is just that - very used and he charges top dollar for it. His guarantees are a mere token gesture. His warehouse type of outlet is packed with kit but it should be examined very very closely.
That is a very negative viewpoint but it is best to be told what to avoid.
If you get into central London around the British Museum there are a couple of shops but you will pay a premium price for whatever you buy. If you are taking any equipment out of the country there is the option of not paying the tax on what you buy currently at 20%. Ask at the shop if you are keen on anything.