Ok I managed to solve this based on a previous post where Tom had deleted files in /opt/fog/{service,etc}
I tried doing the above but still didn’t seem to resolve the problem. So I moved the existing fog folder in /opt to fog.backup. Then created the /opt/fog folder and copied the .fogsettings to it.
Performed a reinstall to pick up the existing settings and it now seems to be all ok without any errors.