u/Crispypiggy

I've got a two, two way, two gang switches. One downstairs for my living room and landing and one upstairs for the same.

There is a twin and earth feeding a ceiling rose (c) and two 3 core and earth's (a and b).

All earths are terminated.

The blue and yellow wires from the 3 core and earth are red sleeved and go into L1 and L2 on the same gang. The red 3 core and earth wire goes into the opposite COM on the other gang.

The black twin and earth is sleeved with red and goes into L1 on gang 1 and the red twin and earth goes into L2 on the same gang.

The other light switch is identical.

Is this safe? Doesn't seem like a normal setup.