In case anyone is interested. I believe 'Rover breakers' in Middlewich have a box of new powerfold mirrors stored away in one of is lockup/stores. When i asked about price he (Andy) quoted £125 each.

He's also got a rack of the Rover V8 nose sections (a la Audi style).

This was about 6+ish months ago so may not have many left as they were being sent out as 'normal' mirrors as thats all he had left