I applied and received an interview request two weeks later. Interview itself was then a week later and was bit over half an hour long. It took place in the International Secretariat in London as I was living there at the time, but would have been possible via skype too. I received the offer a week later and started another two weeks later in their headquarters (great experience!)

It was a relatively easy interview. Duration was about 30 minutes and there were two people asking questions. The conversation mainly focused on how my skills are relevant to the position.