I'm replacing an old discoloured isolating pull switch for a bathroom extractor fan. The old unit has two LIVE wires (in and out) and two NEUTRAL (in and out) as well an EARTH. The new unit only has L1, L2, a COM and earth. Assuming the new unit was just a light switch I checked with the supplier, however, they assured me it can be used as a light or extractor switch. Sorry, i know this is probably a stupid question but an advice would be appreciated.