@66er Thank you, understood. I think I've figured it out though (in case anyone needs a tip who stumbles across this), one of the two traveller wires from the physical switch one will be live, and the other not, so combining those will give me an L i can use with my common going in the SW, forming a single 240v circuit.
Just tested and temps now down 60 when the both lights are 'on' but flood light not activated.
Appreciate the help thanks very much.