Hi Fortuna,
I cant give u any advice about your Diabetes, As im a mum of a newly diagnosed teenager with type 1, However i am an old hand when it comes to Colonoscopys, Endoscopys and all the test that go with Chrones Disease or bowel problems, As i was Diagnosed with Chrones Disease 26 years ago, The tests sound worse than they actually are the worst part is the horrible drinks you have to have to clean out your bowel before the test, The test themselves are painless and no knives ect are involved, You will be fine, try not to worry,
Good luck
Debs D