Realised I was looking at the existing switch the wrong way. I was looking at the connections as top and bottom rather than left and right... The blue, yellow and red all to the left when looking from behind the switch all handle the light on the stairs, while the red and black towards the right handle the lights down stairs. I failed to see a middle vertical line between them due to cables. I assumed the top three were for one socket and the bottom three on the existing switch were for the other. All done, got the it working. Pics show it just as I want it.