Another possible xenon fault -
Since geting my 166 over a year ago one of the xenons has always pointed too low. First step is always connecting the levelling motor correctly and this was done over a year ago by following one of the excellent posts on this site. This brought it up a bit - but have still been driving around with only 1.5 headlights.
Mechanics have all scratched their heads (as none seem to understand xenons) and the fact that only one light was out of alignment means it is unlikely to be a sensor fault.
Finally I took the time to have a proper look yesterday suspecting that someone my have fitted a D2R bulb by mistake. Turns out the actual problem was the correct D2S bulb not being slotted in correctly so was not far enough forward in the holder. Whoever had done it had not lined the groove on the bulb up properly with the holder.
Nice bright xenons now...!