I will guess the wavy line it the sign for AC and is to be the feed but normally in the UK the feed and return go to L1 and L2 so I wonder if this can be used with normal UK wiring.
When we are shown two way switching at school we take the feed to com on one switch then connect the L1 and L2 like for like between the two switches and then feed the light from the com on second switch.
This system means we need a connector block in the first switch to complete the circuit.
So we reverse the switches and feed into L1 and connect L2 to lamp and all terminals are connected like for like so the first switch has two wires in L1 and L2 but this means we need no connector blocks in with the switch.
I will guess the dimmer will work either way but I don’t know for UK method see
http://www.ericpalmer.fsnet.co.uk/Lighting.html which has 3 examples for US method see
http://www.wfu.edu/~matthews/misc/switc ... ation.html and
http://www.electrical-online.com/Fall204.gif the USA always have things bigger than us so they call two way switching three way and three way switching 4 way.
I think there may also be something in projects section.
Eric