Thank you for all the well wishes. I was having a proper wobbly last night - fuelled by self doubt. There's no way I would cancel the statement really, as Attila said, it was too hard won and I know he needs the provision.
Mareeya, it's actually a ms independent, it's just very unique, in that they really do see each child as individual and dyslexia, dyspraxia and ASD do not frighten them. In fact all staff are well trained in ASD and able to talk confidently about how they would differentiate for a particular child's needs. It's an awesome school and I am so glad I heard about it.
Anyway, poor ds was in a right old state this morning, he actually looked green. I managed to gee him along and keep telling him that it was just a chance to visit the school and meet the head, not an interview and nothing to worry about - that he was just to be himself etc. Dropped him at school and explained to his teacher that I had to collect him at lunch time and she told me another child from our school had gone to this indie a couple of years ago, absolutely adored it and thrived there.
He wasn't at all happy when I picked him up, with a list of reasons why it had been a horrible morning, so I took him home and let him watch some of his favourite TV programmes while he ate lunch and we waited for dh to arrive.
We over-estimated the journey time and arrived 40 minutes early, then the HT was running 40 minutes late (he was seeing several families today), so it was almost an hour and a half before we went in. Ds was an absolute star, read the school newsletter and then his book and seemed quite relaxed by then, so I think it worked in our favour that there was a delay, because he had time to acclimatise to the environment before we went in. It's very different to his current 1970's built school, as it's a listed building with high ceilings and echoey corridors etc.
The actual appointment was brilliant. The HT addressed the whole thing to ds and was incredible with him, really taking the trouble to explain things and ask him how he felt about things. Ds took some of his favourite pieces of work to show him and also created a new 'passport' especially to give them. The HT was blown away by ds' work and spent a lot of time telling ds that he shouldn't be so down on himself, because he is obviously very bright, his school results/levels are excellent and he should be really proud of himself.
He also normalised the things ds struggles with by telling him lots of children at the school have similar issues and anxieties, but they get through them and go on to do great things.
Then ds went to meet the LS coordinator and admissions officers while we had a chat with the HT and .... he offered him a place on the spot. He said any school should be snapping our hands off to have ds in it and that ds is a teachers' dream with his good manners, enthusiasm and intelligence. He said the work he brought with him exceeded some of their GCSE students' and the GCSE results for the school are nothing to be sneezed at. He was wholeheartedly unimpressed with the behaviour of the local academy and said it's their loss as ds would have been an asset to their school.
He was really emphatic about the fact that he thinks ds is far more intelligent than even his testing (WISC etc) shows and he can't understand why his current school hasn't seen it and capitalised on it. He was also appalled to hear about all the bullying ds has been through at primary and really keen to tell us that although there will always be a degree of argy bargy with school-kids and ds will need to toughen up a little as he gets older (although as he put it, with plenty of time and careful management and not allowing him to fall during the process) they have a zero tolerance policy towards bullying and physical bullying means instant exclusion. I know he means what he says, because he has turned around a city centre secondary that was in special measures and ended up with children from the school going on to Cambridge Uni - that school also had the lowest exclusion rate of any school in the city.
It was such a massive relief to finally hear someone talking about my ds in such positive terms and recognising that he has so much potential, whilst his primary just want to coast him through average results to make their life easier.
As for them not returning the LAs calls. I get the impression that there was no point, as entry to the school is all down to the HT's say-so, so the admissions officer couldn't tell the LA anything until the HT had made a decision. The HT asked us whether ds had a statement and if our LA knew we were there, so I think he is all about the kids and doesn't get involved in the administration of new intake.
They are going to have ds in for a couple of days or possibly even a week in the summer term to get him used to the school and layout, introduce him to some of his new classmates and do some assessments to help them decide which groups to put him in etc.
So, a huge load off our hearts and minds. Ds is no longer without a placement for September and I might actually sleep tonight! 
Ds has been on a high all evening, having had so many lovely things said about him and knowing that the school really wants him. He says he really wants to go there now and is looking forward to it. 