You can make anything fit with an angle grinder ;)

Thanks for the replies. As I thought, I'll get some spares and go easy on them.

Wipe the new ones with a little grease, anything really and don't over tighten. Just bottom them and nip them a touch.
They really are a nightmare to get out on the 749/999 once the head has rounded.

We know all about that dont we Neil!! Sorry!

Ian

Hmmm, one is completely rounded. Was going to try a screw remover tool if it will fit in.

Unless anyone has any other ideas? Except ones involving Ankle grinders...

Mark.

First try would be a torx bit. Tap it in and see if it bites enough to unscrew the bolt. It sounds a pain, put loosen the clip on and move it out the way for better access.
Once the head goes, it's dremel time. They really can be a pain in the arse :(

As Nelly said, Dremel time. Try and cut a slot in the head so a screw driver will fit. I think they are 6mm bolts so you can get in to it drill the head off with a 6.5mm drill and the mirror will come off leaving the remainder of the bolt sticking out.