I sat my full license exam at the 2019 RSGB convention, and passed!
Final score was 48/58 (83%, pass mark was 37/58). I completed the 2 hour exam in about 45 minutes so I was a bit nervous about clicking the 'submit' button, but turns out there was nothing to worry about, I seem to have picked up sufficient knowledge in my 20 years of being a novice/intermediate licensee.
Now I need to wait for confirmation and apply for a new callsign!