I can't believe everyone is highlighting my supper.....which we are just about to eat!
No IBS here but definitely a tum which reacts to stress or tension, so I try to be careful. I do have a hiatus hernia which I was told is "mechanical" - i.e. it's something that I need to keep in control by weight watching. If I'm overweight, the problem is quite unpleasant, not overweight and when the pressure is off, I don't suffer any pain from it.
Have you tried Cauliflower cheese in a small quantity and without all the other foods with it? Do you still have the same problem? I'd guess that cheese in a cheese sauce is quite hard to digest for most people, also with cauli, eggs, and potatoes. If you're able to eat these things individually without any reaction, then it's possible that the combination just doesn't work for you.
Our Cauliflower cheese is our own combination. It's cooked and drained for this dish, I make my own cheese sauce with a French 'pretend' grated Cheddar, I use Penne pasta instead of macaroni, and I cook onions and bacon bits together but making sure that the onions are well caramelised because otherwise they disagree with me. The dish is then made up in layers, the top layer being cauli so that I don't scorch the penne, I mix some cream and nutmeg into the cheese sauce which is then put on top. It's then baked in the oven.
In the spirit of some Easter hospitality, I am sending you a trial taste for this evening. Good luck.