After discovering its held on by 2 self tapping nuts at the 9 and 3 o clock positions and that you therefore need to approach the problem from behind the badge I googled how to do it and found this video. It seemed simple enough BUT its really difficult to do by following this approach which involves removing the bonnet lip trim and bending the plastic part of the bumper above the kidney grills far enough out to reach in and remove the nuts and then re tighten on the new badge. There is just not enough room to get any leverage on the nuts and I really don't like bending the bumper plastic like that. So I was stuck but thought I'd try removing the kidney grill to see if there was access behind there - lo and behold there was and so the job will now be a lot easier. You only need to remove one grill to get enough access to get a 10mm socket on the nuts. Just need to source a good badge now
So my advice is don't follow this video 
https://www.youtube.com/watch?v=yXSSDYmet_M
