After a week of no hearing in my right ear I went to the surgery.
Expecting to have my ears syringed or whatever they do, I was shocked to find I had a perforated eardrum.
No loud noises. No insertions into ear. Just sitting in the office chatting about work.
Apparently it can happen for a number of reasons and should cure itself. Have another appointment to take a look at it.
Fingers crossed again.