I've made up a 3-gang dimmer switch using MK grid dimmer modules. Switch 1 is to 2 x 40W tungsten lamps, wired 2 way. Switch 2 is to 3 x 40W tungsten lamps, also 2-way. Switch 3 is to 4 x 50W 230v halogen lamps, 1-way. The supply live is bridged across the three L1 terminals on the switch...