If you were to go lurk at Rum Ration, you'll find where this sort of thing is discussed ad naseum on the forum. Link not provided, as you should be able to motivate yourself to find it!
Seriously though, do the same research as you would do for any graduate employer - the website is a good baseline of knowledge for any candidate.
I fail to understand why people get so worked up about the service knowledge test - its a tiny proportion of a 3 day assessment which is looking at your potential to LEAD. Its not rocket science, just some very basic revision work.