Thanks but if u had read the post, all you have recommended has been attempted. due to the layout of my house, I cant trace the fault, nor could 2 electricians. there is only 1 place I can access the junction in a ceiling without cutting holes in my ceiling & that is my lounge where I have laminate in bedroom above. If I connect the live only from working switch to my lounge switch, I get lights in the whole of the downstairs, so I am planning on running a live only connection from the working light to the lounge. This will then give me lights all downstairs. Sadly I have just realised that to remove the laminate above, I have to take 80% of it up (15ft square room) so a lot of work especially with furniture. I cant really cut through laminate & chipboard at same time as my joists run the wrong way for me to cable through to working light, its a nightmare for sure! I can access working light from above, as its under the builtin wardrobe. I am awaiting delivery (today) of a 127mm hole saw & I will cut out a hatch to see the working light from above asap. I might be lucky & see the fault there, if so, I will be happy, if not, laminate removal will be the only answer I feel