Well yes, but....
What sort of switches are at all the other positions for the external lights? Are any of them single gang? If so, make that one(/those ones if there are more than 3 switches) the intermediate(s).
a single storey extension, the layout is this:
From left to right .
1. Main door, two gang switch, lobby light and outside lights.
2. Porch door, two gang. Porch light and outside lights. Intermediate switch for outside lights.
3. French doors, single gang switch, outside lights.
My reading of the wiring diagram is that the intermediate switch has two lengths of three core one each from the other two switches.
To change the intermediate switch from the porch to the French doors requires another length of three core from the main door to the French doors and another length of three core from the porch door to the French doors.
The ceiling is boarded so tricky to install two extra lengths of cable.
Walls are not boarded.
I could fit two single gang switches to the porch, side by side, or use a grid switch?
I could use another make for the face plates, I thought Hager are good.
