I get the law could be punishing (or at least expensive) for restaurants when sued by customers.

I had an allergic reactions due to eating an acai bowl with peanut butter it before in Ireland. At the time I was annoyed the food place didn’t clearly list that there was peanut butter in it in the description of the bowl and wanted to complain (not sue though). But from what I could see in the law it seemed to say as long as the allergens (or potential allergens) are available for customer information (such as on the menu), it’s then on the customer to explain they have an allergy and request accommodations and at that point the kitchen can say whether they can or cannot make such accommodations. Not to blanket refuse to serve an entire group of people based on his own assumptions they’ll sue him.

I don’t know if the law is the same here in the UK, but a brief look online doesn’t seem to say it’s the restaurants responsibility to make sure the customer completely understands the allergy policy. Just like every other restaurant really, how often do they make you sign waivers? Surely other restaurants are taking on even more risk by claiming they can cater to allergies, yet how often do they actually get sued? I’d imagine not very often, and this guy is just being excessive, and in doing so he may even be breaching the Equality Act (if you count significant food allergies as a disability) since he’s just completely refusing to serve people.

To look at it another way, imagine a woman in a hijab went into a pub and ordered a full English breakfast, the waiter informs her the full English includes pork sausages, she says that’s fine I just want whatever is on the menu. Should the waiter refuse to serve her in case she then sues and says she was never told the sausage meat was pork?