In Nehby, they have used SFA framework, if I use SFA as for heading but provided enough points in different sections let’s say a Feasibility reason in the Suitability part, will I be awarded full marks? In the marking scheme, they have said 2 marks for a relevant point. I know it would be better to go without headers in such a situation but let us assume the above example.
I don’t really understand your question. However, if you can identify a suitable and helpful framework, like SFA, then use it: frameworks should help you and they will help the market.
So have major headings for each of SFA, then follow each with your well-explained points ensuring a new paragraph for each. There points do not need headings because they should be self-explanatory.