Well assuming we're talking about an agency or parlour pimp, his position on the food chain somewhere below plankton doesn't really give him much room to criticise anybody anywhere, does it?
For the most part, a punter is a punter is a punter, no matter where you are. Your marketing and screening will do far more to dictate the sort of people you wind up seeing than geography, although AFAIK Leeds is far more saturated than Liverpool.
I've worked in all of the places you mention bar Harrogate (where I've done a handful of outcalls), and the one I did best in was Liverpool by a country mile

. I was so appalled by Chester I left after one day.