Chain Reaction Cycles always have good deals on and pretty much always a sale
Plus you can't argue with free postage...
Warning though, its very easy to spend a lot of money
![whistle :whistle:](https://www.golfgtiforum.co.uk/Smileys/modern/whistle.gif.pagespeed.ce.1ajJ-11lc7.gif)
Asides from that try Wiggle for general kit but I find them a little over priced for parts
failing that hit up your local bike shop and see what they recommend!