Grumpy, just surf the motorsport classifieds on Pistonheads, ebay, track forums etc etc. Loads of R888s around, although they wouldn't be my first choice, they're at least cheap... Yoko A048s, Dunlop DZ03G, Kumho V70A, Pilot Sport Cups and a few others too.
Woody, they're just £20 a set ebay jobs, nowt special but they stop the car getting filthy when travelling. I can't see any on at the moment to link, but I'll find them...