15Q 11.2 Microdeletion.

Good Evening everyone,
I have an 11 year old recently diagnosed with 15Q 11.2 microdeletion. The reason for this post is that I am struggling to get any support from his school and he is on a long waiting list to see his pediatrician. (He has been seen once in 18 months, and as a result we had genetic testing, leading to the finding of this deletion). He is in Y6 in school but only working at Y3 level. His school acknowledge the fact that there are issues with his memory but are not prepared to get Educational psychologist involved. He is on the SEN register and has 30 mins additional support each week from a Teaching assistant. I have fought for years to get support but am getting nowhere. In my opinion he needs assessments to see if he has a learning disability. I would say he has but I am not a professional and without a diagnosis he will continue to go unsupported. Has anyone payed private to have their child assessed? I feel this is now my only option. 
Many Thank, 
Laura.