You should ask them for a copy of their ATCO recruitment CD which I have still got from 2000 in my application pack. Its called 'Skyscape, Your International career as and air traffic controller' with Eurocontrol. I would have thought it has been updated by now but there are some very good quizzes on there which test both your ATC knowledge and aptitude, and it gives a detailed insight into life as an ATCO with Eurocontol at Maastrict UAC. It also contains interviews/ questions with some current Eurocontrol controllers.
Well worth getting hold of before going for your selection I'd say!