Sorry in advance for the lengthy post!
DS is 2.8 dx ASD.
My older DS (NT) is in year 1 at the outstanding primary school at the top of our road and was in the nursery there too. I have a good relationship with the staff in the nursery and would like DS2 to attend. He doesn't qualify for his nursery hours until January as he is a September baby, but DS1 started there in November when he was just 3 as they had a place available, so I know this it is possible for him to start in September.
I made an appointment with the SENCO to ask how I should go about it and just for a bit of advice and support.... which tbh wasn't a complete waste of time. She was patronising, flippant and generally difficult 
.
I'm not that surprised, but now need some advice from the fabulous mumsnet SN people!
I assume I need to start the application process for an EHCP with my LA.
There a few things I'm not sure about:
I have been told that DS needs to be in a professional setting to be assessed - is that true?
Does that mean DS will have to start nursery and struggle before he can get additional support.
Is there a way to have 1-1 in place beforehand or at least applied for?
How likely is it that he will get 1-1 in nursery?
I know when you apply for reception a child's SN are taken into account, can DS get a preferred place at this nursery due to his dx? Or at least the early admission, I think the social aspect of nursery could be hugely beneficial.
Lastly! What kind of reports do I need for the EHCP, he currently gets SALT, OT, music therapy (not started yet but had assessment) plus he has a DP and he is also seen by audiology (grommets) and opthamology (wears glasses) - not sure if that is relevant to an EHCP!!!
He is quite clearly autistic - not a boarder line case iykwim. Nonverbal (well a few words recently 
) uses PECS, little receptive language, no major behavioural problems as yet. Basically a happy sweet little man in his own bubble! Language is by far his biggest struggle, but he is making progress slowly.
I feel strongly that without 1-1 nursery will be basically babysitting him as he will happily sit alone and do puzzles, stim and wander around aimlessly!
He is doing a VB/ABA program at home part time, which has been fantastic. I know that trying to have that included in the EHCP is a whole different battle..... any advice would be greatly appreciated.
Our LA is Hammersmith & Fulham, any experiences of going through this with them?