Hi
I had my assessments in London and the first stage consisted of them checking my documents - birth certificate and education etc, a height check and one group discussion task. The process lasted about an hour and that was it! Then, if successful they called you back again for the second stage which was a psychometric test on the computer, another group discussion and a one to one interview. We finished up with a fun quiz on Austraila. The second stage lasted about 3 hours and then you were told by phone about a week later if you had got through.
Hope this helps!