Thanks for your response, Nancy.

I was also sceptical at first of the food intolerance tests, but after doing a lot of internet research and asking around, I found one in London that used what seems to be the highest regarded method in the field (BER method) and figured I had nothing to lose, doctors hadn't been much help in giving advice!

So far on the no yeast/sugars diet I've been feeling a lot better. I'm hoping that's what the main issue has been.

I did test okay for gluten, and have been baking some breads/cookies at home using whole wheat flour without issues (so far, at least). If I start to feel worse again I'll try cutting out gluten as you recommend.

Other than the occasional home-made piece of bread and tiny bit of rice with some meals (now replacing with millet), I have been sticking pretty much to meat and veg. After a month or so I'll probably try as you say and add a new item in, a week at a time or something.

Thanks again for the advice.