When I removed the wing the other day I was puzzled by the large high wattage resistor in attached between the inner and out wing panels. Bit of research turned up that this is landrover partnumber XBL10003 with the description of "DIM-DIP assembly"... That's was news to me.

Bit more digging and turns out the vehicle was fitted with a Dim-Dip headlamp feature which originated from a piece of defunct short lived UK legislation which required (when engine running) the headlamps to come on at same time as sidelamps at a greatly reduced (dimmed) level of the normal dipped headlamps. Landrovers solution to this was to fit a high wattage 1ohm resistor feed to headlamps via a dim-dip relay feed. The EU forced the UK to retract that law.
Anyway thing is my headlamps have always been working normally else I would noticed this feature before now! Even though it no longer leagally required and probably is a silly feature I still wanted to knwo why it didn't work and also curious as to how it looked. So bit of fault finding turn up that the resistor was at fault - was reading in the high 10's of Meg ohm instead of the expected 1 ohm. Instead of paying silly money in replacing the whole assembly I sourced a suitable 50w 1 ohm resistor (?3.99 off ebay!) and swapped the faulty one out.
Dim-Dip works now! But boy that resistor and heatsink(read whole inner wing) gets hot, so not sure it will live long (would fail safe anyway).
Here how it looks from FULL BEAM - DIPPED BEAM - DIMMED BEAM