Sorry for the delay in my reply, I haven't been on the forum for the winter.
I did manage to replace the compass, but it was a real pain in the bottom. I ended up having to recut the mounting hole with a dremel tool to get a replacement to fit, and did not want to remove the glass from the cockpit. I ended up fitting a Ritchie Explorer compass in. Works great.
Pland on spending a bit of time removing the old old. I had to pry it out and biy, was it stuck in there! I thought at one point that it must be mounted underneath by some hardware as well, but it wasn't.