My sisters polo has just been taken into main dealers because she couldnt get the full beams down, its a 99 Polo saloon. (The 6n Type i think)
The problem they found,(also found on other polos also) was that the switch on the light stalk at the wheel had melted. Common issue it would seem so maybe, seeing as the mk3 stalks are much the same, it may be your bother. It was on the inner part of it.