@WorraLiberty No, I don't suffer from anxiety. I am, however, fully aware of the 'little' things that abusers and bullies do to make their victims feel unworthy, insignificant and isolated.
He doesn't see her as having the right to expect people to use her own name. His choice to call her something else is more important. His choice to call her something she dislikes is more important. And he has got his own snurking mate to call her whatever he likes. And his pathetic, snurking mate's wife has been tricked into mocking her as well, just to reinforce their feelings of innate male superiority.
Deliberately misnaming somebody is a very effective way of demonstrating that they and their feelings, identity and literal facts don't matter. It says they can't be arsed to get it right, they deliberately get it wrong because they aren't worth the respect of using their actual name, they put extra effort into deliberately saying it wrong.
There is an underlying thought here - she is not British. Think of somebody deliberately getting an Indian lady's name wrong, throw in a generic 'foreign' bit - what sort of person deliberately gets an Indian (or African, Chinese, Thai, etc) person's name wrong in that way? 'Oh, what's the fuss about, it's just funny, you have no sense of humour, you aren't like us because you're foreign and don't belong, we're all like this, we love jokes about foreigns and their stupid names'.