Hi, and thanks for your reply.
Of course, it would have been a lot worse if I had ended up with some kind of cancer, that goes without saying! On the other hand, the problem with the coeliac diagnosis, if false, is that any other gastrointestinal problems I have had have been put down to coeliac disease, including suggestions that I have not followed the diet correctly.
Additionally, there are problems arising from misunderstanding, even by close family members. For example, one person was convinced that one piece of evidence for my having coeliac disease was that as a child I had an allergic reaction that seemed to be caused by coming into skin contact with wheat. Of course, coeliac reactions are completely different to wheat allergy reactions (at least as manifested on the skin, e.g. swelling of lips), and are triggered by ingestion, not skin contact. In fact, this incident bolsters the theory that what I actually had was a wheat allergy which I've subsequently grown out of (I must have grown out of it or I'd be dead by now!). I don't actually think the doctor I saw all those years ago was very bright about this, because years later I said to my parents, wouldn't it have made more sense to reintroduce gluten in the form of rye and barley in order to test whether it was a true gluten intolerance rather than a more general allergy to wheat (rye and barley allergies seem to be much less common, so isolating wheat would have made sense).
As for continuing with gluten, I'll wait and see what I'm advised by the consultant. If he recommends continuing with gluten I am happy to do so. Unlike a lot of other people with negative results I didn't notice any deterioration when the gluten was reintroduced. In general, I don't feel well, but I would say that if anything I felt better during the gluten trial, which I would put down to the fact that although gluten itself doesn't have any health benefits that I know of I would guess that the sort of things I was eating would be digested quite differently (e.g. starting the day with whole grain wheat rather than maize).
Other tests have included blood tests for all sorts of things (liver, iron, etc, all normal), stool sample analysis for calprotectin (raised once, normal once, raised result probably the result of rectal bleeding caused by a polyp, now removed), OGD, colonoscopy, examination of mouth, eyes, abdomen, and anus/rectum. None of these have shown any abnormality at all. In fact, I'm told that in terms of blood and every imaginable physical examination (manually or with endoscopes) I am positively a picture of health, so why I have these problems remains a mystery. One explanation that has been suggested is simply stress, though I don't know whether stress would cause these symptoms in the absense of any physical evidence.
You are right that it is very strange to think about eating gluten when for my entire life that I can remember eating gluten has been something that I have believed would make me ill. When I was told I had to eat gluten for what was initially supposed to be six weeks I actually put it off for a couple of days (so was grateful for the extra week at the end to make sure the test was as conclusive as possible). I was mainly worried about other people's reactions, so the first time I did it I went to McDonald's alone to try a hamburger! Then I had to break the news to people one by one that they would see me eating gluten for the first time in over 30 years and not to be alarmed, it was something I had to do for medical reasons. One person who had me round for dinner during that period actually refused to serve anything with gluten, even though I'd told her I had to eat it in order for the test to work properly. It was really very strange. I found myself going into the local bakery to buy lovely stone-baked rolls, thinking, somebody is going to tell me I'm not allowed to eat it!
Thanks again for your thoughtful and helpful reply.