Should I use a structure for my Writing section?

You don't need to, but it will most likely help. Try to remember that the question will ask you to write 'accurately' and 'interestingly', therefore you must avoid getting carried away by trying to add in extra details that don't benefit the plot or characters. Yes, the writing section is worth 50 marks, but that doesn't mean you should write a lot of characters into your story just to show that you can - there is no use adding in characters that are irrelevant to the progression of the story. Follow some suggestions and guidelines like the ones below; Limit yourself to 3 characters (you may include 4 if you absolutely have to). Bullet point the plot before you begin writing and cross off your points as you write. Try to include a plot twist nearer to the end of the story, which can; a) be quickly resolved or b) remain as a cliffhanger. Aim to use 3 words (preferably adjectives) that aren't in your every day vocabulary.