The plot thickens...
Having got back from the GP, he is suggesting that I could have a problem relating to Acid Reflux, whereby acid is getting into my Eustachian Tubes...
This is the best link I've found so far in terms of explaining the issue, albeit targeted at kids:
http://www.marci-kids.com/eerpharynx.html If you find a better link, do post it.
My visit to the GP has reminded me just how complex the diagnosis process is, and
just how little an amateur like me really knows 
Anyway, I do have one or two symptoms associated with the disorder, such as occasional gurgling noises emanating from my neck. I also suspect that my unconventional lifestyle with regards to rarely adhering to regular mealtimes could be an issue.
Anyway...no doubt there are a hundred and one other illnesses that can cause ET problems... Acid reflux is about as plausible as any diagnosis I've found, so I'm now on antacid pills and will see what happens...
I feel sorry for anyone finding this thread - there's no magic bullet - you'll probably have to try a hundred and one treatments to find a solution
