I am a coeliac and am fine with galaxy chocolate and minstrels, in fact they are pretty much on of the the only chocolates I eat!
If possible, I try to stick to chocolate without fillings etc, as they are generally fine (dairy milk normal chocolate etc). You could try going to the allergy section in large supermarkets, I find morrisons to be really good and sainsburys, although tesco has things too. Mrs Crimble's chocolate macaroons are wheat and gluten free and I love them, as do most of my family (my dad is a coeliac too, but everyone loves them!) Also a lot of thorntons chocolate bars etc are gluten-free and they are really good for labelling etc.
I don't know if you have known about your allergy for long, but I have been on a gluten free diet for nearly a year now, and things are becoming much easier - you get to know the products that you like and get to know what to look for more. As someone diagnosed with 'coeliac disease,' I joined coeliac UK and you can get a great little book, the 'food and drink directory' which lists everything you can have. However I am not sure how this works if you aren't officially a 'coeliac' but it is worth checking!
One thing to be aware of is that companies do (annoyingly!) change ingredients often, so keep checking labels! Strangely too, some chocolate bars appear to be fine (mars bars for example), but the 'mini' versions of chocolates aren't! So if in doubt, check labels!!
