Problem is the Main Beam Headlights.
Checked the Steering Column Switch which operates the Lights.
Tested for continuity - all seems well with the Switch - from Power in Pin to each of the 3 Pins in the Output Plug = Side Lights - Dipped Lights - Head Lights
Running separate 12 volts cable to the Head Lights - they work fine.
Problem seems to be somewhere between Switch and Head Lights as with 12 Volts to wiring just beyond Switch - Headlights do not function.
The cables from the Switch to Sidelights is quite chunky - so is cable from Switch to Dipped.
But cable for Headlights is very thin which leads me to think a Relay is somewhere in the circuit - but where?
All Relays and Fuses at Fuse Board OK.
Anyone ever involved in similar situation.
Hope to hear.
Best Rgds.