OK, apologies for the massive post, but I'm going to try and address, from my point of view, a few of the questions raised since I posted last night.
There are many reasons why a child can improve after being given a diagnosis. Again, as I have already said, each child is different, some will need the diagnosis, some will not and will be able to get by being quirky or eccentric.
My BIL has Aspergers, as does his ds. Bil doesn't have a diagnosis, but says knows he has it. He and sil chose not to get a diagnosis for their son. In bil's case, he is and always has been a very strong, independent individual who was able to cope without any additional support. His son didn't need a diagnosis because his father was able to understand him and what addtional help he needed without external professional support. He also attended an inner city school with a high proportion of children with additional needs, that was excellent at providing him with lots of pastoral and other support that many schools either can't or won't supply without a diagnosis.
In my ds's case getting the diagnosis has helped him to understand why he was struggling so much socially, why he felt different than his peers and never quite fitted in. Having a reason why he doesn't understand social rules etc helps him to cope and ask for understanding or support in situations he finds difficult.
Without the diagnosis, his school were not in the slightest bit interested in supporting him properly. The situation is the same at all the local primary schools, so moving him to a different school would not have helped. He attended the standard SEAL group sessions, as did lots of other 'quirky' children and there was some merit in that, but it was nowhere near enough to help him learn the skills he needs to mix with his peers appropriately. For many quirky children in his group, this sort of standard school support is enough, for my ds and for many other children it isn't.
Similarly, the Autism outreach team would not have been able to come out and work with him 1:1 to help him understand why things have gone wrong, as and when they have. The educational psychologist wouldn't have worked with him 1:1 on learning to recognise and understand emotions in both himself and others and to learn to communicate his feelings to adults better so that we are better able to support him effectively.
Without a diagnosis, my ds, a boy who was always just a clever, but quirky little boy had reached the point of mental breakdown and simply wasn't coping. He had gone from being the top of his year in infants, to not producing any work at school. If we hadn't got a diagnosis and intervention at the point we did, he would no longer be in school and would be looking at a very different future.
The diagnosis - or label - effectively acts as a signpost to enable the school system, other professionals and even peers and the wider community to better understand why my son is different and to therefore be more tolerant and understanding of him.
Yes of course, in an ideal world people/children would all be taught tolerance, understanding and inclusion from the start and would be lovely non-judgmental inclusive individuals. Unfortunately, life just isn't like that and currently the attitude towards people who are different and/or have invisible disabilities is actually getting worse - not better. It's a sad fact, that there's far more intolerance and judgment to anything that is deemed 'different', than there is tolerance and inclusion in this world.
I should also say that his diagnosis also came as a huge relief to us, as his parents. Its heartbreaking not being able to understand why your child isn't coping and watching them struggle on a daily basis with things their siblings and peers breeze through. Since his diagnosis, we have been able to learn to understand things better from his perspective and manage his anxiety and behaviour more appropriately. Our relationship with him has improved significantly. We are a much more relaxed, happier family and he is a different child. He is once again achieving well at school and his future is much much brighter. It wasn't that we didn't love him and accept him for who he was before, of course we love him beyond measure and always have and we tried really hard to always give him every bit of support he needed but prior to the diagosis, we struggled to understand why he thought/did certain things and therefore often found it hard to gain the perspective needed for handling various situations and giving him the right support.