Anyone have a spare green wheel center cap I can buy? One of mine has disappeared and I can only
find groups of 4 being sold on the internet.

 

Let us know for sure, is it for your 2001 XK8, or for a different year/model?

We've often found, unhappily, that sometimes a year's difference in the car's release (or it's WHEEL'S production), will cause a center cap to be too small, or too tight.
We wouldn't want to give you a wrong fit cap.

 

FWIW, there are lots of center caps options on eBay. They are cheaply made and wear/fade out in a couple of years, but you can get a couple of sets without breaking the bank.