Strikeforce are good, but
Endicotts rule! I have actually considered making a cross-country pilgrimage just to have a rumage...
Leith Army Stores used to be a lot better than they are now. These days, there's almost no
surplus kit at all - it's all WebTex knock-offs and generic camping kit. They're OK for clothing though - British lightweights, German moleskins, shirts and so on. However, I don't see any reason to buy from them online - they're nothing exceptional. I just use 'em 'cos they're local.