I have bought a new light for the landing, when i removed the old one there was 3 lots of 3 core wires in there. I thought i had marked them and put them back in the new fitting the same as in the old fitting, however, when i switch the landing light on from downstairs and upstairs all is well until i switch on the bathroom or spare bedroom lights, the landing lights go out or sometimes dim and the bathroom light wont come on nor will the spare bedroom. If i leave the landing light off the bathroom light comes on when i use the switch. Any ideas what im doing wrong please.
Regards Mick.