Hi Zoe,
I have a bit of IBS but my daughter has it quite badly.
I take magnesium at night and I just wondered, I take the bisglycinate form, as I believe it's gentler and it's absorbed better.
My daughter uses colpermin or buscopan for IBS there is also a low fodmap you can find on the internet which gives you a list of foods that are better for people with IBS.
Hope that helps and sorry if I've told you stuff you already know, but IBS is really awful
xxxx