I have found it very easy to buy Gluten free products in England at most grocery stores (bigger ones). I got gluten free scones, crackers, breads, cakes, biscuits (cookies), rice cakes, breakfast bars, snack bars, cereals and museli etc. It's been a joy for me because even in the States I have difficulty at times.
Now were are off to Rome tomorrow and was told by my landlord to bring whatever I can because he wasn't sure there would be gluten free things like these at the grocery store. If you have been to either France (Paris) or Italy(Rome) and found grocery stores with these items, could you please let me know?