I'm sure that I used to have overlapping beams from both headlights (on dipped) where they light up the verge, but now there is a very visible difference between the two lamps (not as bright as it should be). Searches reveal a 6mm allen key adjustment somewhere, but I couldn't find it earlier - should I be looking at the back of the light units ?

Sadly, given the wet piece of string that BT call internet out in the countryside, a RAVE download is out of the question at the moment.

Many thanks Scary Stan

Are you sure you haven't been on there and moved the left/right dip lever for foreign roads?

Cappo - you are correct - I have been moving the lever for driving in France and then back to uk mode, which blocks the "angle up" portion of the light which illuminates the pavement ahead of the horizontal bit of the beam on the road in the uk (if you see what I mean) - but (and I checked by moving them up and down a couple of times) that doesn't affect the left/right adjustment where I want the left and right hand lights to overlap exactly.