Gotta tell you guys about my experience with tyres online @ mytyres.co.uk: tyre dealer for cheap passenger, summer, winter tyres
Car passed its MOT yesterday but with an advisory that the two rear tyres were getting low. When I came back from the MOT station I ordered 2 new Goodride SA-05 215/50 R17 95W XL to match those I've got on the front. It was only £113, including delivery and VAT for 2 tyres which is a great price.
Unbelievably they arrived at 10:00 this morning, which was less than 24 hrs after ordering.
Not sure if they deal outside the UK, however if you are in the UK you could do a lot worse than give them a try.