On top with what was said before about the group task, were were advised by the Ctc selection team not to give too much away however I would give a few tips from what I have experienced. I would say that if you are in a team where there are a few individuals who are trying to take the lead and are overbearing - Don't challenge them and make an extra effort to put forward your ideas. The mistake I made in my opinion was trying too hard to voice my opinions which I think came across unprofessional. Unfortunately I felt outnumbered and cornered in the task which is why this made me look unprofessional because of the fact that I was interrupting those certain individuals who were always talking . If you have any individuals who are not team orientated and are taking a lead on purpose , I would just say sit back and let them crack on because it's not team orientated. It's a team exercise at the end of the say so just appreciate the people around you and have as much fun as possible. Good luck to those going to their selection days, no need to panic just be yourself.