I was in a local antiques arcade and one stall had a table covered in binoculars. In amongst them was one pair with Broad Arrow marks, but no other markings. At £20 it was a large punt, but i thought what the heck and bought them.
a couple of weeks later in the local army surplus shop, I had a dig through some ww1 postcards and found the one below. I am certain the chap wtih his back to the camera is carrying a pair of this type of binocluar!
Could only have been better if the King had been carrying them!