Simple CV and covering letter application for the a graduate scientific software developer position, applied after finishing my PhD and I got the impression the process is slightly different if you apply as a graduate without a PhD.
They emailed to arrange a phone interview very quickly, they were able to reschedule to a time I could make with no problems. After the phone interview they quickly arranged a second interview in Abingdon and made an offer within a few days of that.
Phone interview lasted about 40 minutes, consisted of simple questions relating to points on my CV, mostly relating to exact nature of programming experience. There were also a number of technical questions relating to programming - nothing too difficult if you are familiar with the languages you put on the CV. Finally they asked a lot of yes/no questions about willingness to work for a range of clients, away from the office etc.
Interview day mostly consisted of a programming exercise which was fairly straightforward - good understanding of classes/inheritance/etc required, supported by one of their software engineers. This was interspersed with a short presentation, tour, demo of one of their projects, and lunch away from the office. At the end of the day, I demoed the software exercise, and had a short interview with a HR person.
Overall lots of opportunity to ask questions, and the day was conducted in a friendly way with nothing that seemed designed to trip you up.