Help needed with extra wire on starter.

[Spider]

Not sure what the engine is the Land Rover I think it is a 3500 mid 70's Range Rover.
Having trouble with the starter on my Land Rover, when I was looking at the starter it seems to have main power feed from battery, 6.3mm terminal on and brown wire (think this is the starter wire from ign switch).

There is also a 3mm terminal on a brown/white wire, is this for the ballast coil ?