With regards to what to read up on for Cranwell, as well as the current AND FUTURE aircraft, and where the RAF are at the moment, current affairs and your own life are the main things to gen up on.
Your life should be fairly easy, make sure that you plug yourself as a leader and a motivational do-er (oh, feel the management phrases!, it's like a little game of b*llsh!t bingo). For current affairs the interviewers may ask you for one story from the last 12 months in detail, they might ask you for x from home and x abroad or they might ask you for major/interesting news from around the world. Something like, "In headline form, give me some news stories that have caught your attention in the last 12 months."
Sounds like a hell of a lot to learn but the BBC website (other news sites are available) has a good section about past history of the countries around the world. It's probably a good idea to avoid anything in the last two weeks, although obviously be aware of them, and avoid the major RAF things like the Iraq/Afghanistan situation, or they could well as you some REALLY nasty questions about those areas. Something like the expeditionary air wings set up could be good, but don't try and BS your way into a problem.
The Week is worth reading as it covers the world in helpful chunks, but remember they read it as well and interview people either every day or every other day so they now the last two weeks/months news inside out, if you can come up with a news story that is a bit different, like the Veniswalian (sorry for the spelling) flag changing direction, they might perk up a bit and remeber you well.
Hope this helps.