I have uniroyal rainsport 2 225/40 /zr18s @£79 each plus £2.99 per tyre delivery next day
RS2s aren't as good as RS3s, but that's a very good price. A really good price.
I recommend to try thi site, as I believe they're cheaper than blackcircles,
There is no one tyre site that is always the cheapest; you need to look at several, because one might be cheapest for, say, Hankooks and another for Michelins. That said, on average, Camskills is often one of the cheaper ones.
I ended up going through Tyreshopper for the best price.
I've also used Tyreshopper, and found them good. Price included fitting at National Tyres (and way cheaper than buying the exact same tyres bought through National Tyres).
As predicted, National tyres, who can't have been getting much dosh out of the deal, attempted to sell me something else, rear brake pads. As unexpected, it turns out that I actually needed rear brake pads.