The key resources seem to be:
- Painting British & Pakistani Camouflage by: David Blacke
- Painting British DPM by: Keith Forsyth
- Painting Guide - NATO British: by Mongrel Miniatures
The thing I find most amusing about all of this is that they each start with a different base colour.
I'm actually going to follow Tim's Guide, which appears to be similar to the David Blacke method.
I already have the sand base colour done on all of the figures after my disasterous false start.
Note: Check out the David Blacke article as it also covers Pakistani camouflage!