I have never seen a hotel in London where there are lots of WGs (obviously) hanging around. I have been approached, discreetly, by girls a few times in bars in hotels. The Mayfair Hotel on Stratton Street was where one such approach took place. I have seen girls who I thought were working (but never got approached) in the bar of Claridges. In London it is not obvious and maybe, if you area desperate to meet a girl, you are better booking one. Maybe you will find one in a bar, and maybe she might approach you. But no way are there numerous girls hanging around for you to "take your pick". I hope this helps.