What should a school do upon diagnosis?

Hi, I have a six year old son who has just been diagnosed with high function asd, the assessment states that he requires 1 to 1 support in the classroom, he needs a referral for speech therapy, and OT. We have been battling with the school. He is in a mainstream school, they are saying that the report is only suggestions and that they do not need to do what it says, and they are not going to implement any additional support more than what he already gets which is very limited. They are not going to apply for high needs funding and will not even complete an EHCP. I know we can initiate that ourselves but can the school just choose to ignore this report?