I don't usuely visit the allergy section here, but I spied your post and thought I could help.
I am from the UK too. Try Holland and Barrett,they do soya yoghurts,Rice milk and soya milk and also a soya margarine that doesnt taste too bad at all.There is also a section for gluten free bread ,cakes, and biscuits. There is dairy free chocolate too. You can even get sweets that are very similer to smarties but they are also dairy free.