This is quite a find.
A beautiful Webley screw grip with Holland style bar action sidelocks which has seen almost no use apparently. Not bad for a 104 year old gun!
Best of luck in your load development task.

A as side note, I don't think that I have ever seen a pre WWII Evans gun that was not a Webley or Webley and Scott. Evans was particularly fond of the screw grip, just as I am.

Best regards,
WC