After a phone interview dealing only with software development tasks, including OOP and how I would approach some problems, I was invited to an Assessment Centre in London; it was very well organized, consisting of an interpersonal interview (which went surprisingly well, given that I thought I was too blunt about some things and I was unprepared for it), a group exercise (regarding building a software solution, it was a question of tradeoffs) and two technical interviews, one more general, and one that I found very knowledge-based, which went rather badly. After a while I got a phone call and was offered an extra interview, which was not knowledge-based, but rather had more questions on algorithms and problem solving, which went well, and I got the offer.