Two wat light switch cabling problem

[Desie]

Hi Guys

I have two light switches that make up a two way circuit. A builder has taken off the switches and has put them back on but I can't get them to work.

I have in both switches two red strands and a black strand.
There is continuity on one of the reds switch to switch and the black switch to switch. The other reds do not show continuity.
In one switch the remaining red is live but in the other switch it isn't.

Has anyone any idea how I cable these up to work again?

 

[ricicle]

The red and black that are continuous between switches put one in L1 and one in L2 at each switch.The remaining red at each switch will go in Common (maybe marked C)If the light switches are not both in the off position when the light is off swap the wires between L1 and L2 at ONE switch