Hi AP96. I have an identical piece with a small broad arrow above a crown over E (Enfield inspection mark) on one of the tubes. No
marks on the end. i also have the model with the handle for the Vickers or Hotchkiss or Lewis gun with the letters EFD (Enfield of course)
on the handle hinge (a nice solid place to stamp it). More than likely your bore viewer is English made and purchased for use by the
Canadian government and so stamped upon receipt and inspection. Patent infringement applies during war time as well. Collectors should be aware that just because it has a Canadian ownership stamp does not mean it was Canadian made. Web slings with the block 'S' for Savage
used to be common with the C broad arrow on them as well. JOHN