Yeah... an argument an argument can be made that it is time while in the mother's care. Still not so sure about not being able to speak to the teacher though. That doesn't seem right. From the school's point of view the last thing they will want to do is get involved in any form of dispute. How frustrating.
So... if you don't think the school will take a position it's best you find someone that will. A good solution will be to go to the agreed GP. Also get the child assessed by a psychologist. If necessary the GP will refer you to a psychiatrist. If there are issues arising they will identify them. I believe getting independent expert views presented in court are how you will get a solution to this. This can take time so start now. It is also most likely the best way to apply pressure to the other parent.
So... if you don't think the school will take a position it's best you find someone that will. A good solution will be to go to the agreed GP. Also get the child assessed by a psychologist. If necessary the GP will refer you to a psychiatrist. If there are issues arising they will identify them. I believe getting independent expert views presented in court are how you will get a solution to this. This can take time so start now. It is also most likely the best way to apply pressure to the other parent.