Just to tidy up this thread hopefully.

Armandnel, the faulty relay at front right under the bonnet which seems to have fixed your illumination is NOT factory supplied. It has been put into the system by a previous owner (or yourself) to protect the factory wiring/switch which has no head light relays as standard.

The symptoms you describe in a standard defender would be caused by the headlight switch at the steering column. The solution is to repair/replace the switch and install switching relays to protect the new switch from high switching currents.

S