Fuel Sender Connections

Bit stuck as 6 months since I took the tank out - have replaced both rear corners and had to wait for spraying days to arrive.

Putting it back in and noticed I've only got 1 wire to connect to the cylindrical fuel gauge spade connector.
How does the gauge get earthed?
I've got the rubber gasket in the right place so it can earth via the tank, but what earths the tank?
Do I need a 2nd cable as an earth to one of the gauge screws?

 

You do. You should have an earth tag welded to the sender. Earth that to the body.

 

Thanks. Wanted to be sure as it's hard to get back to once the engine's back in.