no, they complained about another member of staff
A member of staff you line manage?
Would it be appropriate for you to tell them to take it up with that member of staff directly?
They also corrected a member of my team in front of a class but wrongly (he was talking about me when he said Miss but they assumed it was them and corrected him) so he was unhappy
I would say to "them" that whilst you understand that titles and pronouns are important you them, it is not appropriate for them to correct members of staff in front of the children and if this happens again they should raise it with the member of staff concerned privately after the lesson.
and the students are just continually being corrected (not necessarily a problem) but they feel very guilty and some of our kids really worry about being seen as intlolerant or upsetting
Again, I would be tempted to raise this with them. Explain that the children are trying their best and it's great that they are learning to be tolerant and respectful of people's identities.
However, the children are there to learn. They are primarily there to learn academic subjects such maths and English, not how to validate their teachers' gender identities, and this is what the focus should be on.
When children make mistakes in maths and English, their mistakes should be addressed in a way that supports them to learn, not by making them feel bad about themselves. If this teacher is making children feel bad for getting their title or pronouns wrong, they are putting their own personal identity above their responsibility towards the children.
It's also worth noting that all teachers, regardless of their sex or gender identity, will experience disrespectful behaviour from children. It is part and parcel of being a teacher. I remember kids at school shouting at teachers, calling them names, and even in one memorable science lesson, throwing the pigs' kidneys we were supposed to be dissecting. I also once saw another student stab a teacher's hand with a biro.
If they can't cope with a child forgetting to call them Mx, they are never going to last in teaching.
They need to develop a thicker skin.