This is a great example of how not to run a brothel. How you as a punter should loiter exactly depends on the area. Standing around on your mobile phone is just newspaper talk designed to titilate the prudes outraged by the newspaper story. Standing around tapping away on a smart phone if the new pastime for 85% of Londoners! The point is discretion. If you go for a walk, say hello or smile to anyone walking their dog, act like you know where you're going, you're a tourist or anonymous fellow resident of the city.
Even I've punted not far from Haringey - that part of london must be packed with WGs offering in calls.