I finally visited Pens Plus in Oxford today thanks to NeilB's recommendation.
A great shop with a good selection of both pens and inks. I resisted the pens (Visconti Van Gogh's but not the Crystal I regret selling everyday!) but left with four new inks:
Herbin Lie De The - I really like this one; nice lightish brown with nice shading.
Caran D'Ache Grand Canyon - umm is this the same as Lie De The does anyone know because I can hardly tell teh difference :-/
Caran D'Ache Blue Night - not entirely sure about this one; not really blue - more of a dark grey with the merest hint of blue, still quite classic though.
Lastly, Visconti Bordeaux - sadly waaay to red for me. I'm sure the cartridges I had were darker than this - I was expecting something closer to Diamine Monaco Red. This I feel will be on the Marketplace shortly.
I guess it serves me righ for impulse purchasing ink and not checking here before I went down there.
Cheers,