Thanks for replies 
I don't think it's because he wants to stay bcos he starts to say mummy time when he's getting upset apparently, but his ok when he comes out.
Open he doesn't say if he likes school or not yet bcos he's not at that level of communicating his thoughts with me yet, but he seems to enjoy going and they tailor every thing to his interests & do lots of fun things with him and he loves his 1-1 so I'm sure he likes going.
I just think it's fishy the getting upset comment only started when they increased his hours by 15 mins & id asked when they were being increased again. so I feel that's what there using as the excuse to not increase again, but unfortunately whether he's upset or not they have to work around it, no I don't want him at school getting upset obviously, but what about in yr 1 or 2 etc when he's still upset, will he still only be on 2.5 hours a day?
He did 2 years at nursery with two of the days he attended being 7 hour days and he was fine well he was fine I don't think the nursery staff were 
I keep being told, the senco or the other teacher who sorts support out is off, but do you know, I'm starting to think bloody hell how much time do they have off! hmmm.
His speech therapist came this week & said to me she works with quite a few other asd children and she's not met a 5yr old on her books on so little hours at school. She said even those without ehcp's were full time and she was v confused by it.
On another note I've cancelled his Salt. The lady was lovely, really nice, obviously very experienced in her job.
But what she's doing at home is what we do every day. So after 2 sessions I don't feel like I can justify paying for something we've incorporated into his life as standard anyway, she comes for 45 mins but ds has v limited attention and I'm constantly getting him and sitting him back down, stopping him throwing, getting him out of her bags and stopping him climbing on her etc she wants him to do her game he wants to do his own thing, he's very difficult to engage and I don't want to be paying £75 a pop while he's doing that.
The Salt was fine, she said she totally understood & I can contact her any time in the future, she said he will mature with time and his attention will improve the more we work on it and that's when the real learning can happen etc. (His attention believe it or not is so much better than 2 years ago, but still very limited)
She said keep doing what im doing she said i was doing fabulous teaching him so that made me feel better as I always feel I'm not doing enough and what else could I be doing with him, she said ds has a good range of vocabulary, she thinks he'll talk 'properly' one day but she said it will take a few years in her experience to really work the language out, she worked with a child similar to ds and he was 8 before he really started talking so it does give me hope.
She said his concrete understanding of instructions etc is were she wants it but his abstract understanding is years behind but she said that's often the case with asd.
She said if he hasn't got a grasp on the abstract language, he won't want or wont be able to speak about things he can't see, this is why he has lots of issues talking his thoughts as it's not concrete in front of him, well it was worded a bit like that anyway, but I understood perfectly what she meant, lol!
I've got lots of things in mind to do for the abstract part and the blank levels what Jeb recommended are fantastic (thank you) so I'll keep doing that and maybe in time I'll book her again.
I explained all this to his 1-1 & she agreed & said since September when she started working with ds she thinks he's doing brilliant and she's really seen an improvement in his speech but mostly his understanding and she said he was a superstar.
So it does make me feel a little less guilty in my decision.
Xx