To win at Tribunal, you will need to have your own private reports because the LA/NHS ones won't be worth the paper they're written on, I'm afraid. They usually play down needs.
The top priority would be to get Ed Psych report. Usually £1000-£1500. Most Ed Psychs have a waiting list of about a year.
After that, an OT is a good bet or perhaps a SALT report. Or a private advisory teacher. They're around about £350-£800 each.
The EHCP has 3 steps to it.
(1) You apply for a needs assessment . Usually, the LA says no. So you go to Tribunal armed with your evidence. Approx 98% of people win on appeal as the bar is low. The child may have SEN and may need support in accordance with a plan. Tribunals are taking about a year to be heard.
(2) Let's say you win at Tribunal. Then they need to assess your child's needs. They produce 2nd rate reports that play down needs. LA say 'needs aren't that bad, we're not going to issue you with an EHCP. You go back to Tribunal. Another year's wait...
(3) Let's say you win that tribunal. The LA issue a plan but it's a pile of rubbish because they use wording such as "Sophie needs access to a quiet room". That doesn't mean that Sophie WILL go to the quiet room. 'Access' can mean 1 minute per year!!! It will need to say 'Sophie will be able to go to the quiet room for at least 1 hour per day'.Your private reports should tie this kind of detail down a bit better. Back to Tribunal you go to get the plan specified and quantified and to get the specialist provision you've asked for and not the local mainstream school that really don't understand SEND! Another year goes by...
So, to get an EHCP, you're looking at at least a year, if you're very lucky but most likely 1-3 years. All while you're being gaslit and offered parenting classes because 'Sophie is just fine with the support she's already getting in school'.
Most parents win at Tribunal and receive an EHCP for their child. But, you will need to be strong to weather the storm. It can take a toll on your mental health.