Fuel sending unit wiring connection

On my 1989 XJS convertible....
I have disturbed the factory wiring, resulting in no fuel gauge operation.
3 wires are connected to the sending unit on the rear of the fuel tank.
The connections are visible in the trunk, behind the forward trim panel.
The wires are Green, Black and Red. Would someone kindly have a look at theirs and advise the order of connection from top to bottom....thanks.