Thanks everyone. Of all the wreckers I called, not one of them said they would separate the mirror itself from the unit.

My car is a gc8 so the gd mirrors wouldn't work but thanks anyway =)

I had a quick look on ebay but couldn't really find anything. I ended up going to a place in Balcatta called Glasscraft. Unit 5/14 Cressall Road if anyone else needs to do the same thing. I just took in the plastic part of the mirror that the mirror itself sits in and they cut up a piece for $25. After that I just stuck some more double sided sticky tape on and popped it back in. It fits inside it quite well even though, as said previously, they cut 3mm instead of the normal 2mm