Murphy23
Stage 3 is a short group test to see how well you interact together, fairly enjoyable, breaks the ice really. Afterwards youare taken off 2 at a time for a lengthy structured interview where you will be asked several questions on each of the criteria mentioned in nats PDF. You need to be able to show specific situations from your life to prove that you can do each criteria.
Cheapaschips, Murphy etc... Good luck with the results, don't stress about how you think you did, I hope you will be fine.