OK, further investigation.
Found light fitting cables in the loft, light fitting into other (suggest ring main) through terminal block, pos to ps neg to neg and earth to earth. pull cord switch is also going into terminal block.
cheers guys.
Can someone help
I'm try in to connect lighting to the pull, cord I've wired the 2 core plus earth , brown to com blue to L1 and connected the earth, the light comes on but when i pull the cord for off position the fuse blows.
cheers all