I am preparing an appeal for my daughter concerning refusal to issue an EHC plan. What case law is there on when it is "necessary" to issue an EHC plan per CFA 37.1? The only case I can find on IPSEA’s website in relation to refusal to issue is Buckinghamshire CC v SJ  UKUT 0254 (AAC) which is about the necessity or not of qualifications, which is not relevant in our case as our child is cognitively very able.
We would recommend taking a look at ‘the Noddy Guide’, which summarises the key case law in relation to EHC needs assessments and plans. Pages 11 and 12 set out a number of cases which may be relevant to you. The cases referred to can be found online using a search engine or BAILII.
In summary, ‘necessary’ means that the child needs an EHC plan in order to get the provision they require. To phrase this as a question: will the child receive the support they require without an EHC plan? If the answer is yes, then a plan is not necessary. If the answer is no, then a plan is necessary