There is plenty of gluten food that is unplatable also. The trouble in restaurants is that wheat,  like the Frank's Hot Sauce commercial; "They throw that bleep on everything." In my opinion, the underlying problem is compromised immune system due to vitamin D deficiency and Green Revolution modern wheat.  50% of the industrialized world are vitamin D deficient and we are urged to avoid sun and limit oral vitamin D intake to the minimum.   Non Celiac Gluten Sensitivity became an official diagnosis only 10 years after modern wheat was marketed.

I understand from one of our forum moderators who is UK-based that the benefits of having an official celiac diagnosis varies depending on your postal code. So then, it must be a benefit tied to local government rather than national government.

I think if I gave up gluten and got a negative blood result and stick with it rather than do the gluten challenge (even though I’ve got no symptoms.. yet).  think if I gave up gluten and got a negative blood result and stick with it rather than do the gluten challenge (even though I’ve got no symptoms.. yet). 

For anyone interested in research summaries on this topic we have this category: https://www.celiac.com/celiac-disease/celiac-disease-amp-related-diseases-and-disorders/thyroid-pancreatic-disorders-and-celiac-disease/ 

Obviously, you have looked at all this from various angles and I respect that. But consider this, you could trial the gluten-free diet for six months to see if it results in lower ttg-iga scores. If so, it is another piece of evidence pointing to celiac disease. You could then go off the gluten fast and return to a gluten loaded diet for weeks or months and repeat the colonoscopy/endoscopy. My point is that trialing a gluten-free diet does not eliminate the possibility of getting valid celiac retesting at a late date if you are willing to engage with the gluten challenge.