Thanks for the replies guys, the selection event was last week, unfortunately I screwed up on one of the tests so didn't get through to group exercise! How, embarrassing... :-x
I messed up on the verbal test, the one where you have to read a piece of text and pick out the facts. The week before I had done a similar test with the BTP, in that you had 25 minutes to do 31 question and you had to get a high percentage of questions correct. In the Virgin assessment you are given 35 questions to do in 10 minutes. Because I had practised expecting a similar time limit to the BTP assessment (the invitation email from Virgin didn't reveal the length of the test, but the example they gave suggested it'd be similar), I had got used to doing them in a rather slow and careful way. When it came to doing it in 10 minutes I wasn't prepared, the time flashed and I stupidly stuck to my slowly, slowly catchy monkey way, I only got just under halfway through and thus failed.
I was especially annoyed as I think I did really well in the other test where you have to listen to a tape of noises, questions and commands, a test which I originally though would be the hardest...
Oh well, you live and learn. I seriously doubt I'd have got the job anyway, I have no previous employment history, yet the other 8 people who were there (2 of which went out at the same stage as me) all seemed to have past railway experience, the majority had already worked for Virgin Trains!