The light in my hall and the light on my landing are both operated by a double switch in the hallway and the same on the landing so that both switches can be worked from both downstairs and upstairs as well. One of the switches on the two way gang upstairs has stopped working so I've bought a replacement but when I've taken the old one off and made a mental note of which wires went where, it seems that two live wires (old red colour) go to L1 and two black wires go to L2 and now I'm questioning myself as to whether I noted them correctly in my head. Can anyone confirm that what I noted to myself sounds ok. It's just that I should have thought that L1 and L2 would both have a red and a black going to them. Thanks.