|Having carried out some more research, I can confirm that the RV8 wheels were "supplied" by Alloy Wheels International (AWI) of Cardiff and not Speedline, as I had previously suggested. Speedline had been mentioned to myself (and also appaarently to David Knowles) as being the probable supplier, but I can only assume that they were a contender for, but in the event did not win, the business. There are several markings on the back of an RV8 wheel, one of which is "AWI".
The detailed position is as follows:
AWI supplied the wheels and Michelin the tyres to a company called Xpress. So far, I have not been able to specifically identify this company and this name may be a "Rover shorthand" for "Express" or "Express Tyres" or similar. This company fitted the tyres which were then supplied to Rover as a single wheel/tyre assembly with the Part # ZKC6752.
AWI also supplied the centre caps ZKC6751 and the centre cap fixing bolts ZKC6754. The wheel nuts and locking wheel set were supplied by Autoturn Products.
The above all relates to the later type wheel, but It would seem unlikely that the supplier would have been changed mid production. If, however, an owner of an earlier car would be good enough to check the markings on their wheels...