The first thing you learn with early intervention is that you cannot rely on the system to look after you, or even refer you to the correct type of therapist or specialist. It all falls on the parents, to work out what to do, and to make it actually happen.
You have the advantage of being the expert in your child, but limited experience in exactly what is developmentally usual at various ages. EB is invaluable for ideas and suggestions.
A screening assessment tool that includes videos of ‘usual’ kids and ASD kids is http://asdetect.org/
It was created by LaTrobe University. This could help you consider any ASD flags compared to a usual kid. It helps you know what to look for.
If it doesn’t seem like your child, you should still be getting a dev paed assessment but start looking into any other relevant things while you wait to see them. The more general understanding of things you have, the better spent your time with the dev paed will be.
BTW, having seen a speech therapist, I would assume your child has had a hearing test? It’s the first thing dev paeds ask for but you don’t require a referral to get one and it’s good to have before you go to the appointment.
Yes he's had the hearing tests & it all came back normal from the audiology side of things. I did the ASDetect & it says "low risk" of ASD. Still definitely going to seek more professional assessments of course. He pretty much does everything milestone related other than the speech side of things which is why we'be been seeing a SP since 18 months because already at 18mo I was seeing him falling a bit behind.