Correct regarding bedroom. I changed the bedroom as above and bedroom is working. However hallway is still not switching off.
I have a multimeter. But if easier should I go out and buy a new one gang two way switch for hallway?
Hallway is wired as you said above. Red in L2 and black into L2, all three red blue and yellow onto L1 left. Not tripping anymore but light isn't working. Does it feed from bedroom? Bedroom is working by the way but maybe wired wrong?