Tony, I can recommend Silvabronz in Alton, Hampshire.
I had both front and rear bumpers triple plated 4 years ago and the results were superb.
Click on the link - https://www.beckworth.net/contact-us.html
Martin
David I'm very interested if I can fit them withount drilling additional holes left by previous mirror.
Does each mirror include one or two fixing bolts and if two what is the distance between the bolts - centre to centre?
Martin