My copy is Dutch too. The individually sold albums were UK pressings. The box set version contains Dutch pressings. The country should be changed to Netherlands.
The individual albums, listed above, were certainly UK pressings with their own individual catalogue numbers and available separately in the UK. The box set however was a Dutch import pressing, and both the sleeve and the album labels had a single catalogue number (CBS 450222 1).
More of a thick card slipcase rather than a standard box. Came with a colour booklet.
Issued in the USA as The Voice: The Columbia Years 1943-1952 on Columbia C6X 40343.