Stereo plate holder

I was at a job recently where one of these plate holders was being “taken apart” to be used for parts in mocking up something else. My face must have been a picture, as the client said “Dont worry we’ve got another three!” At the end of the job he gave me one to go home with.

Anyone have any idea what camera this would have gone with. The size is much bigger than any stereo camera I’ve ever seen… this is roughly 14 x 6 inches. Rather than a sliding dark slide it has a hinged flap?

One of the glass plates is signed F Nicol.