Canon 20D and Grip Problem

I have a 20D with a Canon Battery Grip which I have used for several years. The problem is that the thread has gone on the grip and I can't get it off. (out of warranty off course) I am about to take a hacksaw to it usless anyone else has a better Idea. The battery in the 20D will need changing at some stage still working Ok for now but that day is coming soon.

Anyone got any Ideas?