Advice needed

Without going in to too much my little boy is under the autism pathway at the moment we have completed all assesments and genetics all 4 assesments from the neurodevelopment team and consultants state more or less the same global development delay he is aged 4 but at a level of between 18-24 months in all areas of development, sensory behaviours, obsessive behaviours and repetive constantly. We have just applied for the ehcp ed psychologist went in to pre school for an hour - to observe him. We have always had some conflict with pre school as my little boy 'is not allowed to melt down there' and words from the manager  "I can see it in his eyes but I just have to look at him and he knows not too" anyways the ed psychologist has come back after an hour said my son will manage fine in mainstream school without the support of an ehcp, and basically all the seperate assesments he has had she can't understand because nursery don't present things that way at all. This is so frustrating - as soon as we collect him from pre school he tends to melt down as if he's been holding it in all day!! Things also noted in clinic he was very repetive in speech, speech self directed no repocropal converstation, Eye contact limited and at times took a significant amount of time , top toe walking, arm and hand flapping and finger splaying seen. This is so frustrating pre school seem to think by not allowing him to melt down and making him try new foods although he is sick that this means there is nothing up!!!! How can they disagree with all the doctors.