I am scheduled for a test in Hamburg in late August as well, for a Turkish operator (not Turkish airlines). The sim and the interview was done in Turkey and passed it with flying colors. Now, the toughest part is the cubes, the numbers (not the arithmetic one but the one where the lady reads the numbers).
Is there a software/book/website to study for DLR? I understand that the test is not really 'studiable' but getting a hang of the things would help..