Well, I finally made a desicion after much trying on and deliberation and went with these
http://www.aarondistribution.co.uk/sepia.php
They are the same as the miltary Lowa Mountain GTX -
http://www.aarondistribution.co.uk/mboot.php (which I have had a derivitive of before), but in a brown/olive nubuck. They arrived today from
http://www.polimil.co.uk/acatalog/Lowa_Mountain_GTX_Boots_Sepia_Olive_Green____141.00.html and I am, at first initial try, very pleased.
They fit my criteria - supply enough for kneeling shots, stiff enough for the hill, light enough for walking all day, leather so less likely to squeek, not too high, rubber rand to vend off the worst of the scratches, gortex lined, very breathable, comfy, good replaceable vibram sole and not black/military looking! At £140 delivered I think they are very good value for money too!
Not had nubuck before, always preferred something I can polish, but I hear reasonable things about it with nickwax etc, so time to try something new.
Thanks for all the advice, for me, buying boots is a once a decade (and probably a couple of thousand miles!) affair and each individual needs to get it right for them.
Cheers,
Oly