The Khaki is: Steel Legion Drab, Baneblade Brown, then Karak Stone.
Green: Caliban Green, Black Wash, Caliban again, then Castellan Green.
Brown: Simply Mournfang, Black Wash, more Mournfang.
Base: Scorched Brown (Rhinox), Drybrush Calthan Brown, then XV-88, finally Zandri Dust.
The long grass is Swamp Tuft from Army Painter, the smaller Middenland Tuft. I'll use these two as the main grass throughout the whole army, with some other effects on some models for variety (maybe some of the leaves, new barbed wire etc.). I have tree stumps for 60mm bases.
I'm finally happy, although on the actual guys I think I will add a further highlight to the Khaki of a Karak Stone/White Scar mix, and highlight the metal properly.
Of course if you have any comments I can't actually do any work on them so I am open to any ideas for improvement in the meantime, but as I say, after months of trial and error, I finally love the scheme the way I wanted to when I first suggested it.