The advice I could give you is use your time to get to know every avenue of what can help you. By that I mean the SEN Code of Practice, Children and Families ACT 2014 and your Local authorities requirements.
This all sounds very technical but from my experience (18 years of battling) educational institutes seem to respond better when you quote what the Law states. Many try to put off parents by being nice and quoting "what has to happen" genuinely believing what they have been told (by someone else) as the "law".
The greatest myth of these is the 12 months "Assess Plan Do Review" before any EHC Needs assessment can be applied for. Search for Section 36(8) of the CAFA 2014 to see that there are only two criteria to meet. The schools are told by their local authority this and they believe it. The only caution is that you make sure YOU are ready to answer all the questions and provide the information you can if you start the ball rolling. Some parents use the "12 months" to do this, but you have to make sure the school is doing everything they set out to do from the start. So ILP's regular reviews, parental consultations, outside professional visits (autism team, Ed Psych etc.)
My experience: I have an 18 year old now at college. I applied for an EHCP in primary and was told the normal. Pushed and pushed. Autism diagnosis, APD consultation, social interaction groups. Finally I applied for EHCP only to find school had not been keeping sufficient records so it all fell at the last hurdle.
Ended up with a formal complaint to governors.
Daughter has been damaged by all this, now is on an entry-level course so is at least 3 years behind others. Having to now apply for 18+ EHCP so can remain in college.
Like me many won't want to be "pushy parents" when it seems the school is doing all they can. The problem is that most teachers and staff are good, but systems fail and they can't come back and tell us this, so they keep quiet and time passes... You then get to crunch time after gradually getting more concerned and take action yourself, only to find there are lots of pieces missing.
Start early, get educated, and when you are reassured by decision makers "we have got things in hand" politely ask for evidence. When you are told "it will be 6 weeks" wait the 6 weeks and then ask for progress. Don't accept "we'll let you know", instead state "I'll call you in 3 weeks", and do so.
Use the sites that offer help: IPSEA and Sunshine support. Pay the (little amount) to either subscribe to the academy or watch the webinars that are offered (gold in my opinion). The advice offered (from others) makes you sound like an expert when you ask for things quoting the relevant legislation.
There is in-built injustice in every system for anyone with needs. The system doesn't look at the person - only what they are likely to cost.
An EHCP is your passport to securing the future for you child. When you have one you get "waved through" many blocking barriers. It is a hard battle but worth it. Keep EVERY bit of documentation, don't just stuff it in a box. Index it and read through it. One piece of information in one document can be evidence when completing another form. If you have forgotten it's there you can't benefit from it. Yes, I'm saying you won't be watching box-sets, you will be at the kitchen table, yes, it's tiring work...BUT yes it's worth it for the most important thing we have.