If you go to Coeliac uk you can find a sheet of translations to print and take with you that explains your needs, but most places have someone who speaks good English and awareness is increasing. I've put a couple of reviews on the supplementary board of places we've been.
As Pam says the food is very similar to Greek food. A couple of things to watch out for are; sometimes the rice has little brown bits in it, these are tiny pasta shapes called orzo so when going somewhere new it's best to ask about the rice. Chips are the other thing (as they are here) as some places use frozen chips.
Otherwise there are usually jacket spuds or omelettes for lunch and plenty of choices for dinner.
The people and the country are lovely and if you go I'm sure you'll enjoy it!