Sleeping in her bedroom could certainly help, all you can really do is try it and see how it goes.

I really second looking at the custard, check for an colouring called Anatto or 160b. It is a natural colouring but a baddy. I find it really affects my eldest. She can tolerate it occasionally, but not all the time. So you might find if it is in the custard that stopping it will not see an immediate result, it may take some time to get out of her system.

Good luck, I hope things improve for you