Fred:

This rifle was built by Webley. Webley rifle no. 10483 was built for Gibbs and ordered 1902. No. 10737 was built for Evans and ordered 1904. No. 11397 was built for Evans and was ordered in 1906.

I think no. 11170 should be from 1905. By the way, these early Webley's usually had this same number stamped on top the screw-grip fore-end lever. Rotate the lever out to the side and you should see it looking from the top. What is the Army & Navy serial number on it? If I'm right, it should be reasonably close to 45000?

Does your rifle have shoe-lump or chopper-lump barrels? The reason I ask is that the early Webley double rifles had shoe lump barrels, but they seem to have switched to chopper-lump about the time your gun was built. No. 10737 had shoe-lump, and no. 11397 had chopper-lump.

Would love to see pictures.
-----------------------------------------------------------------------