Applied through a recruiter, got the appointment within a week. The first interview consists of a handwritten test, which I took at the G-Research offices in London. The sample questions posted on their website give a good idea of the areas covered, but most of the actual questions are easier. Still, the time limit is tight and it's necessary to prepare well. I spent too much time on easier questions and did not get a high enough score in the end. The overall atmosphere was very pleasant though.