First you sit an online aptitude test to qualify for the group interview. Standard mental maths, sequences, missing diagram type questions. Then I was invited for an interview with 3 other candidates. We first sat through a presentation about the company and its place in the industry and what we would be doing if we received an offer. Then we sat a series of tests. One aptitude test similar to the online one, one testing ability to follow programming-style logic, one asking for a way to program a card game, and one requiring one to come up with a communications system for a particular scenario. Afterwards we were given individual 1:1 interviews going through and discussing our answers to the tests, and trying to improve them. A little time was spent asking about my educational background and CV. I should say there was VERY little time given to complete each test. This was apparently on purpose. Lunch was provided and travel costs refunded.