As to going up behind the Dash then its much more likely that he has picked up the wrong circuit as the Dashboard is on the IG1 circuit as you need that powered during Starting itself, there is a Black/Yellow wire which provides the power to one of the three connectors for the Dashboard
and hence the problem. He obviously hasn't thought about what a L/B charging relay needs, but knew that he would find a fused supply to the Dashboard there which came on with the Ignition, however you don't want the L/B trying to help the S/B run the Starter Motor which wants several hundred Amps when it is first connected!As to the blowing fuse with the Fog lamp, is this the rear fog lamp switch ? The front Fogs have there own connector and switch in the wiring loom (if fitted), whilst rear fogs are an add-on and hence tend to have connections as chosen by who ever fitted it - which means they can be any colour and fitted well or poorly
