Got myself a multimeter and checked - you were all right - live and switch were the wrong way round on g2. Could have sworn I checked that but I guess not!
Thanks for all your help and for not being too patronising!
Thanks a lot, I've just realised that it is a bit more complicated as there is another single light switch piggybacking off of the 3 gang switch - only found this out as it s function is also dependent on the position of switch 2 on the 3 gang! Now I know the logic for how the circuit is...
They are both like the one on the right, but one is upside down. I didn't just rewire like for like e.g.Top right to top right, I thought I had labelled where each wire had come from and made sure it went in the right place on the new switch but something has obviously gone wrong!
Each...
I've just changed a 3gang 2 way switch, and thought I'd copied the wiring from the old one, but it's not working right. Switch one works fine. Switch two also works fine, but switch 3 only works when switch 2 is on. The old switch had a short wire connecting the commons on switch 2 and switch 3...