Some advise please

My 12 year old was assessed last Wednesday and they are now treating her for ASD, anxiety and depression, she has been the same since being little but it was never picked up on until I kept nagging for her to be referred it took 4 years to get to the appointment last week. She started high school last year and started walking out of lessons, this went on and is still going on now, they did put her in the special unit with the school last November until February where they told me her work ability is to good and can’t go back in the unit again, so now we have it were she is walking out of 2-3 lessons everyday and most of the time she will go back into class but she struggles with The noises. She gets really upset and angry all the time. Any advise on what to do? I would prefer her to go to a proper special school where there is less in a class and she would hopefully benefit from it. But the school are having none of it.