Dull dipped beam on a 97 525tds please help

Hi i have a 1997 525tds, the headlights on dipped beam are terrible giving out a dull yellow beam which when faced with oncoming traffic results in me losing view of the road!! , a meter check has shown the voltage to be correct, the bulbs themselves have only a slight film on the inside and are adjusted correctly, there does howerver appear to be a hazy build up over the magnifying lense the middle lense and the outer plastic enclosure cover, attempts have been made to clean these but in order to do the job properly the whole unit needs to be stripped down..... is this possible by myself with very limited mechanical skill/knowledge.
The full beam is functioning perfectly... well at least i think it is, it lights the road up fantastically.
Any help would be greatly appreciated