Thanks thebax. Those maps you linked to are wonderful. I had intended this map to be the first map fo the complex, but as PCs explore the blank areas get labelled little by little and new passageways start to emerge, especially those leading through the lower levels - as a result it might get very complicated, so I have intentionally tried to keep things extrememly simple at this point. Perhaps the drabness is a result of this.

The symol at the top of the map was supposed to be a dwarven shield - to indicate dwarves. The one at the bottom right was supposed to be a mysterious horned helm, which may or may not indicate dwarfs. Obviously I have to redo the shield. The underdark is supposed to look like a drow symbol - so that's good if you got it. I don't want the symbols to pop out - I want PCs not to quite be able to work them out - yet.

What is the difference between the white passages and the more darkly colored passages?
Ok so its clear my map does not work - I was trying to differentiate between well-kown and well-travelled areas, and more dangerous areas with my use of lightness and darkness. I'll need to rethink this completely.