I think I'm reaching my limits. Beers (Den Haag) began importing Diamond T trucks in the 30's as well as Chenard-Walcker vans and Chausson buses after WW2 and built its first Handyvan in 1954 on a Scania-Vabis chassis.
I never saw this oplegger before. The tractor seems to be Diamond T, judging from the small diamond on the grille and the trailer could be made by Lamboo, as for this GMC. But I dont't know anything more about this Vliegende Hollander, probably used on the seashore.