156 head light beam pattern

Dear all 156 owners,
I had a real shock this week, as I took my immaculate 2001 156
sportwagon in for its first mot test.
I have owned this car from new, and only covered 5700 miles, so no
wear and tear
almost as new.
The tester refused to pass my car as the front off side head lamp beam
pattern was "flaring" how ever he agreed that the actual alignment was
ok according to his light tester box, but the actual pattern was not
acceptable to pass the mot.
I have checked the part numbers of my head lamp units with a main
dealership, and they are the correct part for a uk rhd car, they
suggested that I check to see if the bulb was installed correctly, ie.
with the tag at the top in the bulb holder, it is, but just to be on
the safe side I did rotate it and returned for a free re test the next
morning, still failed, so at the test station I once again rotated the
offending bulb and they rechecked the beam
pattern, still no pass, but the beam position is correct, as the
tester agreed.
So what is the answer ? unless some one at the factory fitted a unit
with a faulty reflector I cannot work out the problem, the nearside
light is perfect, the aim of both is correct.
Any one else experienced such a problem on a 2001 car. ??
Please answer because I need to re tax asap.
Martyn.