Old Guy,

You mention “hidden screws”. On a English made boxlock you would first remove the trigger guard by unscrewing the woodscrew/s from the trigger guard tang.

Then lifting the tang clear of the wood and rotating it gently you will probably find the whole guard unscrews around an integral threaded stud just in front of the triggers. You may have to pull the triggers back to get sufficient clearance.

This exposes the trigger plate with machine screw/s attaching to the top tang of the action.

Removing the stock should then be straightforward.

Parabola