PRE DIAGNOSIS PLEASE HELP

Hello. I have a little boy who's three. Looking back there were signs something wasnt quite right. He didn't sit until he was 10 months old he started to crawl at 13 months and learned to walk at 19 months. This past year we have really noticed things just aren't quite right especially with having an older child I shouldn't really compare the two but it's do difficult not to when things are so different between the two children. My little boy will only eat beige foods waffles, noodles, chicken or chips. I try to offer the healthy meals we have but he physically gaggs then will go in to a meltdown. I give him a daily vitamin and he does like some fruit. He has an obsession with red London busses and will sit for hours and watch the wheels turn on them he has a large collection. When we go out in public he just wants to sit on a bus all day and it's a big challenge trying to get him of a bus. If we go in to a supermarket we have to take a red pepper an actual red pepper that he will hold once we are in the supermarket it all seems too much and he will cover his ears and tell and cry and shout OH NO. Trips out he will have no danger awareness at all and I seem to feel anxious on busy roads. He was doing quite well on the potty but a big step back and he's refusing to use it so back in pull-ups at age 3 and 1/2. His speech he doesn't respond to his name at the 3 year development check she said she would refer him to hearing. He can hold a small simple conversation he just looks like he doesn't have a clue what you are saying and won't respond back. But knows a massive range of vehicles and can tell me the names of many vehicles. Other than that his speech can be quite babbily and not make much sense although he will say drinky for a drink and say outside to go outside but can't say can I have a drink or I want to go outside. When the nursery nurse came out to do his development check these things were picked up on immediately I didn't even have to say anything. He was having a 'bad day' throwing things around screaming burst his youghurt all over myself and the nursery nurse all because she moved something from its place. We have been refered for an autism assesment as everyone seems highly suspicious including my self. He is such a delight and when he gets exited he bits down on his dummy (has a big attatchment too) and flap his hands and make noises. The nursery nurse refered him as urgent but they wouldn't accept it because he doesn't meet the regression criteria and have put him on the standard waiting list which is 12 months!!!  I'm unsure what that means but to me since his referral the stopping of using the potty and back in pull-ups it's a big step back. Also people can be so rude people - strangers have come up to me when he's struggling and with his hands on his hears asking me to control him and think of others. The referral is 12 months wait, I'm so anxious as we apply for his reception placement in December although everyone's preety clued and think it's autism without a diagnosis until then it's so long to wait in limbo with no help no advice and no support for him starting pre school and then reception. Can anyone advise please can we speed this up? He is such a delight and he will always be precious but I just want the support for him in education settings. Thank you so much.