hello mate,
as there are 5 wires in total from a 2 core and 3 core cable (red and black is the 2 core and yellow, blue and black is the 3 core plus two earths), and the light switch has 2 times com/L1/L2 ie L1, L2 COM and another L1/L2/COM per light fitting im guessing i need a wire to cross...