I think the answer lies in the scenario and your course title. I would be looking at explaining a basic layout for two different types of premises with a detailed layout for each of the headings and example calculations for each such as a worked lighting circuit design for an office where detailed work is needed (go into lux levels and colour rendering etc with regulations or guidance quoted as a source)and a maybe something like a medical practice (talk about medical supplies possibly and disabled access). then just use different examples and calcs for each of the headings Lights, Small Power, Fire Protection, Security and so on. ( Don't forget all the other stuff as well like Em lighting, heating, alternative supplies etc if applicable)
Hope this helps, typical open ended C&G question.