After some advice please.

I've fitted a battery on my ZS track car, and initially had some issues with the lights (they all didn't do what they should). I realised it was a bad earth, sorted that and they all work as they should, other than the side repeater only on the passenger side.

The bulb is constantly lit, and I'm stuck as to why. I have tried:

Replacing bulb
Cleaning contacts
Checking earths
Changing indicator stalks
Checking fuses
Changing indicator fuse

I'm at a loss as to what else it could be, other than swapping that section of loom. I think there is just the single earth for it, but the drivers side functions fine.

Any suggestions as that what else I need to try?