1996 Espace No Headlights, sidelights or tail lights

I have a late Phase II Espace. While out the other night all was well until it was parked for unloading. When we came to return home, the engine was started and then the lights were turned on and nothing came on. No main or dipped beam, no sidelights and no light indicator on the instrument panel - normally a green for lights on and a blue for high beam. On opening the door the warning buzzer didn't sound. The following day I brought it home and checked the fuses. All appeared OK. I suspected the switch on the steering column and found the horn wasn't working either. The thick red lead to the switch appeared to be carrying 12 volts but nothing on the 3 output leads. Replaced the switch with a new unit and still nothing but the horn now works as does the radio which hasn't worked for months! This evening I have noticed that when I turn the lights on the 12 volts disappears from the red lead - no voltages on any of the connectors. According to the circuit diagram there is very little in the main beam circuit. Supply comes from always active +12 volts, through a couple of connectors (location unknown) and then to the switch. Connector R10 is shown as carrying all cables as well as the indicators which are working. Any suggestions as how to find the connectors as I think it must be a feed problem as the supply is split into 3 separate circuits after the switch. I have the later type fuse box set in the top of the glove compartment.

1996 Espace No Headlights, sidelights or tail lights