hi
You probably already know, but it is usually the gluten in wheat that causes problems for affected people - and gluten is also present in other grains like rye & barley, so just going 'wheat free' may not cover all the bases.
This link
http://www.vegsoc.org/info/gluten.html
has an useful list of common 'gluten free' & 'gluten containing' foods.
another list of grains, etc, here
http://www.coeliac.co.uk/documents/a...s_april_08.pdf
Luckily EU food labelling rules enforce labelling of food offered for retail sale, which contains gluten - but not take-aways, restaurant food, etc...