Ah no that's a pity. I'm not in the UK so I wasn't sure if it was something available to you there.
It's so popular here, it makes no sense why it's not available in the UK.
Good old Buscopan also works for pain although obvs getting to find the triggers is the end game.
I'll list a few of my no no's, maybe they are similar for others :
Bananas
Any skin on fruit , so things need to be peeled, ie apples etc
Onions , absolutely never ever raw (causes agonising pain) sometimes ok with small amount cooked
Broccoli, cauliflower, Brussels type veg
Any crisp flavourings, can only eat plain salted
No bread, rye, or any of these types . I don't even eat gluten free as it's a risk
No wheat, although I do sometimes use flour to thicken things but cornflour is better
Watch cereals , they sometimes are triggering so safest to have oats, well cooked.
I have rice and corn pasta , never normal wheat semolina type
In a hurry not too long ago I grabbed to go sausage roll. It took me about 2 weeks to get over that mistake. Not just the pastry but additives in the sausage.
There are more but you get the gist. It seems quite limiting but it's something you just get used to. Worst is if going somewhere where snacks are provided. Most of the time these are wheat based, and are very tempting.
Is your dd also suffering with diarrhoea and/or constipation? Both are equally debilitating at times. I'm a combo of both so I have to be careful with food mixtures too. If I do ever have cheese, I absolutely cannot have egg in the same meal.
Many people brush ibs off as a bit of stomach bloating, maybe some trips to the loo in a hurry. But it is truly can put me out of action for a few days if I'm having a serious flare up. Sometimes it's so bad that I just won't eat anything as it is just too painful to. Yes stress is a factor but I think diet is more so.
Good luck to you and your dd. I know it's just awful and I hope you find a way forward soon.