Wiring of a Pull Cord Switch?

The pull cord switch in the Bathroom was broken -

So I brought a new one and took the old one out. To my surprise I found more cables than I thought -

I have three grey cables coming down from the void above -

1) has a Black, Red and Earth
2) has Black, Red and Earth
3) has Blue, Brown and Earth

The old one had the three earths together, both reds into the same, both backs into a block (can't remeber where the brown and blue went)

On the new unit I have L1 & C and Earth ?

Any ideas on which should be wired to which ?

Thank you