The picture put up by jstamper of the proof marks does not show a chamber length in the original London proofs. Thus this proof does indeed date back to 1904-1925. In 1925 the chamber length was added, otherwise, the same marks were used.

JS;
As you are setting the cut-off date on the makers address the dates of 1904-1917 may well indeed be correct. Going only by the proofs it would be 1904-1925 which includes your dates.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra