Diagnosis

Hi everyone, I am hoping for some advice, my son is 2 and a half, doesn’t speak and no signs of speaking and walks on his tip toes a lot, covers his ears at loud noises and is a very picky eater. I had a great health visitor who noticed these thing and refered him to all different agencies for support, he is getting blood test at the end of the month for possible anemia. He has been referred to speech and language therapy and I was told he’s on the waiting list which is fine as they gave me advice on how to encourage the speech, we do the tasks but not working as of yet. He has been referred to the neurodevelopmental team and again on a wait list, i phoned them to see how long the list was and I was told oh at least over 3 years, which I am disgusted at, it should never take that long for any one to be seen about anything. I feel in those 3 years my son could have support if he needs it, so has anyone had a private diagnosis done? And if so where? I stay in Scotland.  I had read somewhere the nhs won’t accept a private diagnosis but not sure how true this is. I have written to my local politician about the waiting and also to the nhs about the waiting times.