@tamsin
Regarding gf oats: My daughter was told to avoid them after diagnosis for a year or so, then she had to eat a certain amount every day for about 10 weeks and only after bloodwork showed no antibodies she was cleard to have them on a regular basis.
Same thing will be done for gluten-free wheat starch at some point.
I know this is handled different in other countrys (we're in Germany), but maybe it's worth a tought.
Only about 50% of coeliacs can handle gf oats and/or gf wheatstarch.