What you describe seems like a standard 2way light so first you need to
ensure the new switch you have purchased is to replace a 2way switch (some
are only 1 way)
It should have 3 connections (not including the earth terminal)
These can be marked in different ways but are normally along the lines of
L1 L2 Comm or L1 L2 L3
You state Load Slave & Live (must be a foreign switch)
You could try the following..(TURN OFF POWER)
connect cable1 yellow to LIVE
connect cable 1 red and cable2 red to LOAD
connect cable 1 blue and cable2 black to SLAVE
Try the switch & the 2 way operation with the switch at the other side of
Failing this FYI the red/black cable 2 is the switch wire from the light
(hopefully) to check this just short them together and apply power and the
light will come on permanently.
The 3core cable 2 is the strapper cable to the other switch.
The way the system works is simple ;; the 3 wires of cable 2 join the 2
switches L1-L1 L2-L2 L3-L3 or more commonly COM L1 L2.
Each colour going to the same pin on each of the 2 switches.
The switch wire from the light (cable 1) now connects (1 wire in L2 & the
other in L3) along with the blue & black from cable 2.
To simplify identification if you look at the rear of the old switch
the cable connections form a triangle IE 1 top centre
& 2 bottom left & right.
The one at the top centre is the Comm or L1 terminal and switches between
the bottom 2 terminals L1 & L2. (L2 L3)