our dimmer switch stopped working after 7 years so went to replace it at the weekend. When I opened it up, the black wire was in the common slot and the red wire was in L1 which i thought odd because i thought it needed to be the other way around. Anyway as it had worked for so long that way around I wired the new dimmer the same way, black in common and red in L1 and for a few days lights working well. 4 LED bathroom spotlights and one extractor. however now they are flickering and then switching off. Should i swap the wiring around?