well, i do not get in touch with my host-family, but we got a sheet where everyone should write on, what is important for him or her, for instance people who are allergic to fur will not have a host-family with a cat and so on. i wrote that i am a vegan and explained what it is. i share the host-family with two other guys who are "vegetarians" (in fact they are not real vegetarians but the english food has such a bad reputation that quite a lot of my class mates wrote on the sheet that they want some vegetarian food). my former english teacher who organises the trip promised me that he would do his best that he could find a vegan family for me or at least a family, where i can eat my own food.
i'm already active as animal right activist and in touch with the austrian vegan society. there i can buy the "vegan passport". this passport will help me to say what i want and is also helpful if i want to order food in restaurants, which are not special vegan-restaurants. the passport contains many different languages and- of course- english as well.
well, thanks for your help and best wishes