Pregnant Then Screwed - March of the Mummies

I have just found I'm pregnant with my second child. I've been working in a special needs school for boys who have been through the foster care system. I've been there for 7 months and just passed my probation. It would be very difficult for me to work from home as the students would be unlikely to engage but I've already been punched in the stomach on two separate occasions and kicked in the vagina to mention some examples. I really don't feel safe working face to face with the students. I have told my boss and he said to leave it with him and he would send me a risk assessment over Easter and speak to his line manager about what they should do. My boss is a nice guy and he's not stupid he knows it isn't safe but I'm worried the people above him will try and make me carry on working with the students or turn on me in some way if I refuse to. Does anyone know what I can do from a legal standpoint?

I'm in SW London & would love to know if anyone else is going to the London march on October 29th? 🤗