if cant find anywhere, mytyres, black circle are web based company, buy the tyre of them and thell send it you for around 35 quid, then local tyre place to fit for around 7 quid.
im basising prices on a 15inch tyre.
yeah - all brand new - check out www.mytyres.co.uk and www.blackcircle.com (i think or co.uk) put in your tyre size and away you go.
My tyres tends to be slighly cheaper as delivery is included in the price.