I have managed to sort out the issue.
With your suggestion that it could be a bug, I searched with different keywords which landed a couple of hits.
After holding down Alt+Ctrl+Shift during startup I managed to clear the preferences thinking that would solve the issue.
However the issue persisted until I restarted my computer once more, and lo and behold, the issue was fixed.
So for anyone who may have the problem in the future, clearing the preferences and restarting seems to fix the issue.
Thank you very much for all your help and time.