Hi martin, I will have to delve into this more closely. They are the same wheels as fitted to orion 1600E's but a few sizes larger, I will try and find out more on them from my local dealer I have also seen the same wheels in 15" fitted to a moonstone RS500 that was in performance ford some years ago now. I am by no means doubting what you say but I will get to the bottom of this and let you know. But I must say just because it was not an option on the 500's does not mean it was not from Ford in there Rally sport brochures as you and I both know there were no optional extras on the 500's just a good race catalouge of after sales parts! anyway hope all is good with you and your collection! did you ever go for another motor to replace the moonstone one?

Nick