Can my child be exempt from music lessons?

My daughter is autistic and has significant hyposensitivity to noise. She is now in year 7 and find music lessons very hard. She is an expert masker but comes home following music and dance

highly dysregulated. Yesterday, she came home and punched a single pane glass window in our house because she just didn't know how to channel her frsutration. She won't wear ear defenders/earbuds as she feels self conscious. I have requested that she can go to the school library at this time as an alternative but school are saying that she needs to access all curriculum subjects and that they do not have the capacity to supervise her for alternative arrangements. I am in the process of applying for her EHCP with support of my friend who is a qualified SENDCo. Her needs are complex and at her primary school she had 1:1 support for 70% of the timetable. I am at a loss as to what to do to help her. Has anyone had any similar experiences and can offer guidance? 

Many thanks