Hi shibs and welcome to the HW :)
I have had to do the elimination diets but things got so bad in the end I had to pretty much elimiate everything all at once (not the most sensible idea) but it worked for me and now it's so much easier to determine what I'm intolerant to and what I'm not. It is very hard sticking to a bland diet but if it helps then it is worth it in the long run .. and you do get more used to it. I do know all too well the frustration you feel right now. But stick with it :)
Have you actually had any intolerance/allergy tests done yet?
Could your Primary doctor not refer you to a GI if you were to ask?