its not wired wrong because its been working fine for years ,then all of a sudden its doing this . the wall switch at top of stairs should turn the bedroom light on and off , and the pull switch near the bed should also do this . but they only do this if the opposing switch is in the on position ( i think , its actually at a pensioners house , so will check tomorrow) . i have installed a new wall switch and wired it exactly the same with photos and swapped the pull switch with one i had spare but still doing the same . i may try a brand new pull switch tomorrow just incase the one i had was faulty , or could the pull switch i have installed be a one way ? it had the same terminals as the original one , would this cause the same issue ? thanks for your help