Here are some available geo domains with high populations:
Countries co.uk and org.uk (over 7 million population):
cotedivoire.org.uk - 17,298,000
serbiaandmontenegro.org.uk - 10,829,200
tajikstan.co.uk - 7,163,500
tajikstan.org.uk - 7,163,500
Cities org.uk (over 3 million...
few left over > dev traffic for designers / material / decorators / interior design etc etc
army-green.CO.UK
falu-red.CO.UK
fern-green.CO.UK
fuchsia-pink.CO.UK
han-purple.CO.UK
navy-blue.CO.UK
slate-gray.CO.UK
tea-green.CO.UK
pm us for donation details if any good and anyone regs :-D