When buying any used camper we always recommend taking along a damp meter these are cheaply available from Ebay at £6 and simple to use and can save you a lot of money and act as a bargaining tool.
Try everything electrical you can, ask about heating and water systems, and decide if its been lucky enough to enjoy winter storage out of the elements or has been damaged in the past
German campers in a range to suit all cabin layouts
High end German design, sought after and holding value for years, nothing much to report as yet