Hi Mick
Many good posts on this already, not least because anyone who has experience of a child on the spectrum will doubtless empathize with the issues your family will likely face and wish to offer support/advice. With this in mind, I will offer my own experiences that may help.

Our youngest son, who is now 18, has aspergers. We first became aware that something might be amiss when he was at nursery but, obviously, many children do not settle easily at first and it is harder to formally diagnose at this stage. When he moved into his first year at school his issues only worsened and a friend suggested that he may be on the spectrum which led us to investigate further. Through our own efforts and research we decided that he may well have aspergers. One of the people we found useful was Tony Attwood and I recommend you check out his books or site for more background on aspergers particularly. We downloaded some test questions from various sites on aspergers and used this in discussions with both his school and GP. Ultimately this led to us gaining access to the local childrens clinic and an O/T as well as him getting a Statement of Special Educational Needs (since replaced by the EHCP).

Regardless of having an ECHP however (which is a must-have if you are to get any help at all), so much depends on the individual county councils, individual schools and individual teachers. We have met some brilliant people but they have all been hampered by lack of funding and ever increasing workloads. Some SENCO teachers have been really good whilst others have obviously done a few courses but are proof that "a little knowledge is a dangerous thing". The then government proclaimed that "every child matters" but -surprise, surprise-this was an empty tagline with no money or resource to support it and, as we are all aware, funding for education-particularly for those with special needs-has been continuously eroded. Anyway, it became obvious that his particular school could not meet his needs and so we made the decision when he was around 9 to take him out of school and home school him. Believe me, this was not a decision we took lightly. Apart from anything else, my wife had to give up work which then caused us ongoing financial difficulties. Importantly, we still continued with annual reviews and his EHCP but any government promises of a "personal budget" to help support us did not materialize and we had a long and frustrating struggle before we finally got funding for 6 hours home tuition. The government spend 5K-8K per child per year if they are in school but if you home school you get jack. My argument for funding was that we only took our son out because the school system was failing him and so to not help fund his education was discrimination.

I have tried to post some tips/advice that may help but maybe I typed too much and system only accepts so many words so will try and add as a separate post!