This is an excerpt from 2018 examiner report about GSA:

“Candidates are advised that their answers should be precise, neat, clean, readable and no extra, unnecessary explanation was required from them. Extra care must be taken while selecting a question to answer. Candidates should elaborate their answers using graph/diagram/table where required. Answers of all parts of a question should be systematic and cohesive; not written randomly in scattered places of different pages.“

I would say 1 to 1.5 pages for a 5 marks question is more than enough if you are relevant.