And as an add-on to Robin's last post, when considering the 6 news topics, try and find something slightly obscure, as well as something that is all over the news. At the time I went through OASC, there were some troubles in Cyprus that weren't exactly headline news - I mentioned that and that's where we went. The interviewers will have heard "Iraq/Afghanistan" for the previous 10 bods they've interviewed but if you come up with something slightly different, that may be a way to steer the interview.
Word of warning: Still know you're stuff on all of the subjects!!!
Best of luck
