We recently had this problem in Sweden: There are parking spaces where "Caravans" or "Campers" are forbidden (because they either tend to stay there all day or sleep) - we have a VW T4, it is considered of class "car" in Germany. We still sleep in it. Are we allowed to stay on these parking spaces? We decided: No. Our interpretation was that overnight-stays are unwanted by the local population or government. But the sign wasn't clear. The pictures on these signs also showed no vans, just big campers.
To me, it is as simple as the questions in the link. It is a van. You sleep in it. It is clearly a camper van. In my opinion, anyone who disagree are doing so to be edgy or cause problems just for the sake of it. Of course, there are a lot of those kinds of people.
