First part involved 3 Codility questions.
Then was invited to their assessment center for a two part exam. The first part was using their own assembly style language, you were given a couple of basic functions and you had to build new functions using only what you have been given, just remember you can also use functions you have previously created yourself and it should be fine.
The next part of the exam was a paper based java exam, where you had to write an implementation for a linked list.
If you pass the exams you get a tour of their warehouse, followed by a short HR interview (~30minutes).
If you did acceptable on all of this then you receive an invite back for another interview session, which involves both a technical interview, and another with a manager.