Thanks for the replies.
A fair amount has happened since my post. The main thing, thinking about the consultant's mention of pressure in the cochlea, I held my nose and applied fair positive pressure - it always cleared - but this time I left it sustained for half a minute or so. The improvement was astonishing, but not permanent of course.
That evening after my hike, I sat in the car and listened to a Chopin nocturne - the first time in months it would have been of any worth at all.
In haste now, but I'll certainly write to the chap and tell him about the general anaesthetic link and indeed my notion that I could squeeze some of the pressure out of the cochlea.
Oh, BTW, when I got my copy of his letter (describing me as this pleasant 76 year old gentleman! Yeah, right.
) to my GP I saw his qualifications. BSc FRCS and a lot of other stuff.
I suppose I'd better be diplomatic in my persuasion efforts.