In reply to colina:
I've just bought a massive load of stuff (entire new bike build from bare frame up) from various shops. Chain Reaction are reliably cheap and have a huge stock. Merlin Cycles are sometimes even cheaper (some real bargains) but have a much smaller range. I also discovered nextdaytyres.com who have a phenomenal range of tyres (as you may have guessed!) and good ways of browsing them by category, something which most online bike shops are woefully poor at. I didn't find any stores that offered very good searching or browsing options.
