AFAIK it's Breitling only, unless you are very lucky on eBay.
Expect it to be £££. I asked for a dial change from grey to silver on an Aerospace I sent to BUK for service, and I think the quoted cost was something like £850, so I didnt go ahead...
Might be cheaper to sell yours and buy the one you like, lock-stock-and-barrel.
PS I have never seen a yellow dial Navitimer...???