Ammo box ID (Well i assume it is an ammo box).

[motto]

They are an unusual box, not an efficient use of volume and awkward to move about with the handles on the sides instead of each end. I would be interested to see one with the contents. I've yet to see one with any markings on it apart from the makers stamped information.
The Bren magazine box is more conventional and has stencilling to tell you what it is but they do have one thing in common and that is a greased felt seal for the lids.

David