Unfamiliar wiring in a 2 gang switch

[MattJ]

I'm trying to convert a standard two gang switch to a two gang dimmer, but the four wires in the original switch are confusing. When I open it up I see;
Earth (fine)
Red wire into the top L1, with another, short stretch of red wire going across to the lower L1
Blue wire with a short red sleeve going in to the top L2
Yellow wire with a short red sleeve going into the lower L2

Both L3s are empty. How would these equate to the L1, L2 and C that I see twice over in my 2-gang dimmer? (Homebase instructions are truly awful)

A big thank you to anyone who can help.

 

[breezer]

make a note / drawing first then put the new switch the same as the old one except L1 as you have is now C and L2 as it is now becomes L1

and dont forget to put the link in too this applies to both switches (but only one link)

 

[MANDATE]

Hi Matt,
Breezer's already solved your problem, but to help you understand for the future take note of the following.
1. A one way switch has only two terminals Com and L1
2. A two way switch has three terminals Com. L1 & L2
3. A two way switch can be used as a one way by ignoring L2 ( L1 if you wish)
4.When you have 2 two way switches together as a gang one of them is inverted, so you have Com at the top and Com at the bottom and likewise for other terminals L1 & L2. If they were both the right way up they would be easier to understand.
5. Each switch needs a 'live' input and instead of having a long wire to each switch it is easier to have one to one switch and then a short link from Com to Com.
6.Red 'sleeves' on wires indicate that regardless of colour they may be 'live' and are known as 'switched live'.(after switching on)

It appears instead of markings Com / L1 / L2 yours is L1 / L2 / L3.
The fact that L3 is empty indicates they are used as one way.
Hope this helps.