i wouldn't say it's possible to attain a high band mark unless you analysed form as well as structure and language. that post above was insanely good, and complicated and detailed - and if you know what you're talking about, it'll really really help you. but i don't think it's necessary for your analysis of form to be quite as sound and complex as that - mention of genre, narrative etc more simple things should be enough. but if you can understand and use things like mentioned above, it'll really put you on the examiners good side.