Here is a picture of the way the British acceptance stamps look on a non refinished .455 MKII. If the OP's gun had not been refinished the stamps on his should look more like this. The only stamp, other than the crossed pennants that I can make out is the II on the frame. Indicates to me that whatever happened to it after, it first went to England where it was received and stamped at Enfield. And while I appear to be beating a dead horse here, there is no reason a 2nd Model HE in 45 Colt would have been sent to England for service in WWI. If it went to Canada we should see remnants of Canada specific stamps; maybe better pictures would show them.
Here are a couple links to previous forum discussions of Canadian marked 2nd Models:
.455 Mk II Hand Ejector markings
Cali Gun Show find HE 2nd model 455 Canadian Stamped
Looking forward to better pictures.
Jeff
SWCA #1457