The uniform in jgeratic's post looks fresh out of the QM's stores! British battledress cloth faded rapidly in use. Try looking at the various "WW2 in colour" programmes shown on The History Channel and similar, but bear in mind that old colour film fades too!
British battledress khaki drab
is a dificult colour to get right. I tend to use Games Workshops acrylics when hand-painting figures, and for this colour, I usually start with 2 parts Camo Green to 1 part Graveyard Earth. I then take some of this colour, add a touch of Catachan Green, and make a wash to bring out the shadows. When these have dried, I take some more of the basic mix, and add some Komando Khaki to dry-brush the highlights.
This is one of those questions to which there is no 'one right answer'. Like I said, look at the sources and make your own mind up. It doesn't matter if the colour of the uniforms differs slightly from one batch of figures to another. This happened, and still does. When I was in the mob, there was quite a range of shades in the DPM uniforms of the lads within my own platoon!
Cute and cuddly, boys, cute and cuddly!