I would like advice from forum members please. Will it be legal to replace a domestic (built-in) single light switch with a dual switch and use one switch for the existing 250V light and the second switch for a 12V stand-alone off-the-grid emergency light (e.g. a solar panel, battery and LED strip light system), provided of course that the two switches and wiring systems are TOTALLY isolated from each other? An alternative will be to install ceiling mounted pull switches, which I do not prefer for aesthetical reasons.