pull cord to light switch?

I am trying to swap my pull cord to a light switch on the outside of the bathroom. When I removed the pull cord there are 2 black wires connected together to a terminal block, 2 earth wires connected to the casing of the inside and two red wires connected to com and L1. Should these two red wires be kept seperate and ran to the outside of the bathroom and connected into a normal ligth swicth under com and L1? Any advise would be much appreciated.