Brief assessment with interview (about 45 minutes). Very formal process, the recruiters came from the HQ in London. It wasn't unpleasant and I received positive feedback at the end. Unfortunately for me someone had more experience and got the job. Regardless, just try and stay cool. As long as you try and research the kinds of answers to give beforehand you will be alright.
Also note the skills and behaviour questions aren't exactly the same as what you are being asked. They are similar but you would have to adjust your answers accordingly.