I do not know whether some guys are interested in preparation classes. However, I attended one of those and passed my assessment easily. If anybody is looking for professional assessment preparation, I can highly recommend the guys from Airline Entry Training. They offer live online classes for the DLR and Interpersonal test which starts from 99€ per day. The website is in German. I was able to translate everything with google. The classes are offered in English as well.
Cheers