I'm not kidding, Mumsnet is such an amazing resource!
I note that uva ursi was mentioned earlier on, I too tried that, and cranberry tablets and every other bloomin herbal remedy in holland and barrett, and nothing made me any better. I think with IC, it's a case of trying what works for you. For example the IC website states that chocolate can be a trigger food, luckily it isn't for me.
Hellsbelles You sound completely like me when my troubles all started. It co-incided with me coming off the pill as well as me doing a juicing diet, but I believe it was the overloading my body with the high potassium/fruit acids that caused it. But, in saying that it has made me crazy in the process of discovering what the problem was. The least little thing and you are over analysing what it could be that is upsetting your bladder. Also - and I say this tongue in cheek, but with a little seriousness - can you think of anything that you are 'pissed off' about? You don't have to share, just a question for you to ponder. I stopped having baths, only showers. Watched which sanitary products I used, ie no tampons - too painful. I used to think they were squashing my urethra and this would make me need to go.
VivaLaBeaver getting a scan is a good thing. I hope you are alright.
Tomhardy I am so glad you found this thread too 
Something which I don't think anyone has mentioned yet is any pelvic imbalance. I mean to say that if you had ever suffered any fall, or trauma to the pelvis or back - this can actually attribute to bladder issues. I'm not saying this is the cause for anyone, but an avenue worth persuing if you feel it may pertain to you.
Also, and I must have written 2000 words in this post
is what I was originally being tested for - a urethral diverticulum. When urodynamics failed to see anything wrong - after bladder retraining (despite being in constant pain and desperate urging 24/7), antispasmodic bladder drugs etc I was advised that the Urologist thought he may have found a small pocketed area in my urethra. I had 2 MRI scans and both were inconclusive, so I lead myself to self diagnose as IC.
Anyhow - for those of you who may be interested, more info urethral diverticulum
BeenBeta Thank you again for your words of kindness and support. I really wish that I was on mumsnet whilst I had the issues. In some ways I am still learning. I will look into the links you have provided.
I am keen to see how you get on with the prelief. This could be a whole new positive experience. From what I see it might allow you to enjoy some of the trigger foods? Maybe 2 glasses of wine instead of 1 with lots of bottled water? 