@TwoCables This reply is being written long after your thread was posted, but contains an important health-check heads up for you.
I'm glad you had improvement of the symptoms you described, including frequent heavy night-time urination. But did you know that frequent heavy night-time urination is also a very common symptom of the serious disease diabetes?
Untreated diabetes can cause major problems, including organ failure, if left untreated over a period of years. Diagnosis is simple, you just tell your doctor about your symptoms and say you'd like to be checked for diabetes. You will receive a referral for a urine and blood test.
Whether or not the preservative TBHQ was in fact a contributor to your problems, we don't know. Single subject 'experiments' like yours do nothing to eliminate the placebo effect, and merely skipping your high non-complex-carbohydrate snack before bed may have alone helped lower your blood sugar levels (cf diabetes again!), thereby increasing your chance of better sleep, irrelevant of TBHQ content.
And even should TBHQ be a (resolved) issue, it doesn't mean you don't have diabetes as well.
I looked at the so called "factsheet" about sleep disturbance & insomnia webpage you linked, and see that it's scientific basic is very, very dubious. It quotes apparently reputable sources, but only a handful of them, and only few pages of each at most, certainly not enough to prove that most of the voluminous list of food additives listed on the webpage affect sleep in any way. The anecdotal evidence listed (none of that is even for TBHQ) is not scientific and proves nothing. The word 'fed' in the website address gives the misleading impression that it's some sort of government website. It isn't.
So please get a medical check-up promptly, if you haven't already (from a GP, since they are all trained in scientific medicine, not some self-appointed New Age 'expert). Be sure to tell the doctor about the frequent heavy night-time urination, whether or not it still occurs.
