You have had some good advice. Virgin place a lot of emphasis on the interview - they want to see what your like for themselves without some third party telling them that they think you'd be a good manager and like otters! Virgin is a purely long haul airline, sitting next to someone for eight hours at a stretch raises some CRM issues that don't exist in short haul. Therefore, the interview is very much a 'W@nker filter'. If you fit this category, they will see through you and anything you try to do to prepare yourself is wasted effort.
You will of course be asked some tech quetions, both general and relating to your previous aircraft types and also stuff like "tell us about a CRM issue you have experienced and how you resolved it". There is no excuse for not being prepared for this. But generally, the interview is a very relaxed affair and not an unpleasant experience.
But if you really need to know what else the day consists of, you will be given a psycometric test (not much store is given to this) and a tech quiz which is more or less just to keep you ocupied while you are waiting. It's not hard, and some discussion amongst the group is allowed - even encouaged. Don't be the guy who sits there with his arms around his paper with a 'don't copy from me attitude'. That's not good CRM! There's also lunch, much of the selection is done here as well!
Before anyone else points out, I got in so the selection process doesn't always work!
It was the most pleasant and informal airline interview I have ever attended, and probably the best. Good luck, not that you'll need it if you're the right person.