17" BBS monza valves

[Johnb1704]

Hellooo! I really hope somebody can help I've got an early mk5 gti (04) with 17" BBS monza alloys and 3 out of 4 valves are completely knackered, I've gone to at least 3 different tyre places and they've all told me I'm better of buying on line the trouble is I'm not entirely sure which ones I need, can anybody help please???