I have just bought a Eurolite single gang light switch and triple gang. The problem is that they have a different number system on the back from the switches I am to replace. Eurolite switches are numbered L1 at the top and L2 & L3 at the bottom. The old triple gang has three blocks of 4 holes, with 1 & 2 at the top and the same on the bottom. How do I correspond the holes with the new switch? Regarding earthing the brass plate - is it ok to leave the earth cable attached to the metal box at back and via short earth wire attach the brass plate to the metal box.