Lots of action makers copied the screw grip concept. HB&P, Osborne, etc.
If you can see course threads on the spindle when looking at the recess in the action for the barrel extension/grip, it was more than likely made by Webleys.
The two piece spindle/top lever is Webley patent, but again, lots of makers borrowed this design after the patent ran out.
It’s very possible that Chas. Osborne made the gun/action as they were prolific makers to the trade. There might possibly be clues to the action/gun origin stamped on the inside of the action itself.
