Ok, so you're going for the more traditional formulas then?
I'm sorry I have no experience of this make. I've always used either F&B or "Earthborn" clay paints.
In most cases, texture isn't as important as some think. If it is, then chalky/clay paints can't be beaten.
If the only issue is colour, then I wouldn't dismiss the idea of scouring through paint charts and especially colours that are mixed to order at most paint outlets.
All you need is the British Standard colour number to get it mixed.
I have to disagree with annie about grey. It's no more "over" than white is ;o)
The one I've used in my own house is a "RAL" colour. It's just another bunch of colour numbers to choose from. (I have it mixed at my builders merchants.)
Also, Dulux have come a long way with their various heritage/traditional colours.
Sorry I'm not being of much help here. I really don't know about Little Greene. I just wanted to point out that colours are available from a load of different sources.