Does anyone know where I can get new centre caps for my 17x8 XR wheels other than fron Ford?

are you after the original metal ones or the later version that were plastic?

Fleabay has them under tickford.

the steel tickford centre caps were made by trammel tooling based in Wingfield, south oz, just off Cormack road. I know they stopped making them when the plastic versions were introduced.
Could be worth a phone call to see if they could make some more, or any old stock laying around...