Regardless of the intent (humorous or otherwise), I know that the British legal system is way, way harder on things like this than the US, especially if there is issue of libel involved. Sue. Even if there is no damage to your reputation, these numbnuts are using your image for promotion or gain and you were not notified or compensated in any manner.

And then when you are finished suing, I will hop the pond and punch the pub owner in the face.