Is it possible to be angry by proxy? If it is, then I'm a shining example. I don't think I can bear to see another online post about a coeliac going to a restaurant claiming they can do gluten-free food and can't. It'll make me scream. (Quietly, of course, as I don't want to ruin other people's Xmas cheer.)
There seem to be 3 types of restaurant ignorance:
The place that advertises gluten-free, has a gluten-free menu, and then turns out to cross-contaminate everything by using the same toaster, grill plate and deep fat fryer.
The place with the clueless waitress who tells you there's no gluten in the turkey main but gives you a stuffing ball on top.
The place that won't even give you a banana because they say it's been in a kitchen that handles gluten.
I'm not sure which sort of restaurant angers me most.
It's especially annoying if you've phoned ahead to check with a restaurant that they understand and can cater for your needs.
The question is, what can you do about it? At Xmas, we tend to be with friends or family and we don't want to ruin a special day/night out. It's not like we can force a whole crowd of people to get up in protest and magically be transported to a gluten-friendly restaurant.
Unfortunately, there's not much that can be done at the time, especially at Xmas. You just have to make it really clear to the restaurant manager there's been an error and why they need to rectify it. There's usually something you can have, even if it's not what you'd like, but I think it's better to be safe and not hungry. Sadly, rectifying matters will probably have to happen post-meal.
So here are my top tips on how to deal with things:
Find the e-mail address of the restaurant's customer services (if they're a chain) or the highest person up in the business. E-mail them in a friendly tone but make it clear what they've done wrong and how they can change their procedures. Here's an example paragraph (feel free to copy & paste it into an e-mail!):
Please could you train your staff across all branches to be fully aware of the effects of cross contamination? Anything labelled gluten-free must not have come into contact with anything that has gluten in it. When I visited your café, your gluten-free mince pies were sitting next to some pastries that weren't gluten-free. Either gluten-free goods need to be separately wrapped or you need procedures in place where nothing can cross-contaminate them (there are always dangers of cross-contaminating by using the same tongs for all food).
Wait to see what happens after you've sent your e-mail. I'd allow 2 weeks for a response (after all, this is Xmas and they're probably super-busy. If they not only apologise but also reassure you they're changing their procedures then I'd probably leave things there, especially if they offer you a freebie the next time you visit.
If you're not satisfied with their response or you feel they haven't appropriately altered their procedures, it's time to take further action. Depending on the situation, you can either contact the FSA or Trading Standards. You can contact Trading Standards via your local council. If you live in Bristol, this is the link to use. Once you've done this, the restaurant will need to satisfy a registered professional that they comply with guidelines including those on the labelling and provision of gluten-free food.
Of course, the above points don't cover the example I gave earlier of the place that's so terrified of breaking the law it doesn't think any of its food is suitable for you. This really is a judgement call on your part. If you talk through their concerns and you feel they're being overly cautious, you may feel it's safe to eat their food (although you'd better be sure!). My personal feeling is if they use airborne gluten in the kitchen (like flour) then it's probably not safe to trust the food they've produced. However, if they don't use flour and separately pan-fry you a steak with some new potatoes which have been boiled in a different pan from anything else, it's probably okay.
If you do manage to get a restaurant to change its practices, let me know below - I'd love to hear your 'wins'!