Hoe lang is Lauria cylindracea al in Nederland?

Lauria cylindracea has been known to occur in a small area near Domburg (Isle of Walcheren, Netherlands) for at least seventy years. It is most unlikely that this locality is a relict area of a larger range of distribution and the author suggests that Lauria was introduced much earlier, conceivably as stow-aways by British army units on their way to European battle grounds.