Best of luck MiggHD. Let us know how you get on.
Murdifi - I know this costs but if you want the best prep for the assessment day I strongly recommend this >>
SkyTest® - Preparation Software for DLR Test (Lufthansa, Austrian Airlines, Swiss, Turkish Airlines, Royal Jordanian, SunExpress, DFS), Cargolux, FEAST (Eurocontrol), Austro Control, Skyguide mainly because CTC use the exact same tests as the ones on this!
I personally didn't find the tests too hard, but I practiced a lot with the above product.