To stop people calling anything a camper van, and inly having to pay a quarter of the road tax, the Dutch Tax people insist on there being a square metre of floor space with headroom of 1 metre 70. (for small Dutch people?)
Though the Mercedes is large and heavy, inside we were 12cm. short of the required height.
Solution; a square metre box on the roof. Good place to put a hatch for air and light, and it'll be hidden behind the roof rack anyway.