Exactly what he ^^ said, the "Something silly" is the blue wire breaks away from the connector at the alt end. The dash warning light is part of the charging circuit, it excites the field windings that start the charge process, the blue wire is the ground for this light.

There is NO reason in the intermim until it can be sorted not to drive the car as you can get the charge process to start by revving to around 4000 RPM.

You now know about the fan rewire and also you need to check the fuel pump voltage under load to make sure it reflects the alt voltage or ideally rewire, this suffers similar problems to the fan circuit, which can result in a melted engine.

Martin