I have recently attempted to change a double light switch that operates 2 sets of lights in the living room independantly. I was horrified to find that the new light switch had totally different parts to the one i was replacing. However, i have managed to put the right wires (4 red and 1 earth) in the right holes i think? after many tries and both lights now work as they should. The problem now is that when i reset the mcb for the downstairs lights, that includes those with the new switch, the kitchen and dining room lights now wont work at all   Any help / advice much appreciated

Have tried many configurations and eventually found one that allowed the other downstairs lights to work   and the wall lights switched on and off with one switch and the ceiling lights switched on and off with the other switch although although one switch swiched lights on in the on position and the other switch switched lights on in the off position - to get to this stage has taken hours - however when screwing switch to wall using metal ? screws the lights do not work again as they should .
Does the metal screw form part of a circuit when contacting switch and bit you screw it to.The switch is earthed

How about some pictures of the switch and the wiring?