I think we may have figured out the problem but we recently replaced a ceiling rose in the bedroom and now when we turn on the bathroom light it flickers and then goes out and the bedroom light either comes on dim or flashes. Any ideas and could it be we have wired into the bathroom feed (and got the switch wire in the wrong place), we did not replace any of the wiring only the rose. And yes I have told my husband to buy a multimeter 
