Just really common-sense approaches to tackling the case study will help.
Put everything out your mind until you've finished reading it. Then think about the kind of issues that it discussed. e.g. "Mr Jackson has been worried that his pig farm supplies business is declining, after Mr Potter opened his newer, more mechanical factory next door." - What do you think may be some issues, just looking at that single sentence? Introduction/Growth/Maturity/Saturation/Decline model; competitors; market trends; effect of technology; health and safety?
Really the only way to think about it is dumping every bit of theory you know, just before you begin to read the case study, then picking it back up as soon as you've finished it.
I'm pretty sure that if someone said to you "Write about stakeholders, or the decision-making process, or the effect of marketing", you'd be able to throw down tons of information on tons of pages. However, the problem is that the exam is not looking for this - they're wanting to find out specific information. Just look through the case study, think about what they're trying to get from you, then look at the questions and see if it all matches up. A really good thing to have is a highlighter, and if i've said it once i'll say it 1000 times - don't be afraid to tear the paper apart so that the questions sit side-by-side your answers, or so that you can look at the question while writing your answer etc. It's your paper; the invigi's can't take it away from you until you've finished.
Hope this helps, but seriously - don't worry - there's still plenty of time before the 3rd of June.