Other than the fact that there is no sim check these days, the Virgin interview process has not changed for several years, and has been covered many times here.
I'm not going to give out exact details of what you may face, as, for a start, it's not much different to most other airlines and, perhaps more importantly, what's the point of having an interview process if you know exactly what's coming? We want to see the real you, not one that's constructed from various hints and tips you've collected!
There are exams, there is an interview. It takes less than a full day and it's fairly relaxed. If you are confident in yourself and your knowledge, you'll be fine. If you're a bit weak in any area, do something about it. You need me to tell you this?
Scroggs