And it was hugely worth it!
As we thought, Sam is particuolarly bright (as opposed to what the school told us, that he was of low ability). He sailed through all the tests of letter recognition etc in a one to one setting, it's just at school in the crowd he has problems. Hardly a surprise with Aspergers! He also had physical abilities in some areas that were over two years (that's the stage they gave up testing, could have been more) beyond his age, ditto language skills.
There were some thing that we hadn't identified: problems with specific types of movement, for example. Those we can now work on.
they seemed surprised that despite having a dx Sam had no contact with the school SENCO (she is the other class teacher in his year, he cold have been in her class had they decided so). We also have letters to the school encouraging them NOT to make him drink orange squash but to make a rule exception and allow him to bring apple juice (he doesn't do water), and suggestions for them to get a visual timetable and allow Sam time out when he needs.
We have some great stuff to do with him to help his reading and writing, and feel we will make real progress.
DH was very doubtful of the idea before, but by the end of yesterday was grinning all over. The whole family went (had no over for school pick up etc) and was accepted, it was a great place with a really happy atmosphere. Somewhat smaller than Knowle Hall, but that wasn't a bad thing IMHO.