I've used protyre in the past, but only because I knew a guy in the Plymouth branch (Gupa P) Use their website to get an idea on some prices, get some tyres in mind, and then ring around your local fitters and see if any of them offer a better price, Bear in mind that some places won't include new valves and disposal in their quotes so do ask.
As for Tyres, there was a HUGE thread about it not too long ago, When I was looking I narrowed it down to Falken ZE914's, FK452's, Kumho KU39's, Toyo T1R's, and some Yoko AD08's. Then the trade off between price, grip, longevity, noise etc lead me to the ZE914's, and they've been superb.