I still think it sounds like your current GI requires current suffering to acknowledge you have IBD and not IBS. What's his/her problem with accepting your testimony of what's happened the last few years? I understand they may benefit from present ulceration or exudate, etc...but that shouldn't be a requirement for you to be treated. They should do a scope, and accept what they see along side your own account of what you go through with this up and down, and also combined with the fact that you've had at least one time where they looked and it was inflamed. It's already been proven you've had at least one doctor note present inflammation. All that should be adding up, again, big picture. Scar tissue or a bloody stool should confirm more than IBS is at work. Blood tests too, your SED rate, things of that nature, should be factored into an assessment, not "oh, uh, well it looked okay this week, so I don't know what to tell you, nothing we can do right now, maybe we'll catch it later and know more then"....
That just sounds like myopic incompetence, with all due respect to your doctor(s), they should be focusing on the big picture, and not require a patient to be suffering (nor considering a trigger of said suffering) just to get proper treatment. If it's come to this point where you're considering worsening yourself because they need validation of severity or symptomology, something's wrong. What about blood tests, you should have some recourse here besides triggering inflammation?
Even during remissions or mild flares, some scarring or something should be present. Kev took pictures of his bloody toilet bowl after a BM to prove a point when he was scoffed at for supposed "exaggeration" of volume of blood.
I'd say let them see what they see, don't inflict damage or interfere intentionally, it could create an undesired result in a multitude of ways. They should be looking at the big picture, I'm not understanding their logic, by nature this disease is episodic, so the fact that they are putting up a fight to diagnose something dependent on how you're doing during a given week is questionable, and seemingly not considering the obvious (that you are flaring and then you're not) or checking blood, etc.. is odd. Why isn't a claim of 1.5 years of bleeding not lending you a right to IBD treatment for inflammation?