If you have a bit of patience you could try fabswingers.com
You have to set up a profile but don't have to show your face etc.
Among the genuine swingers there are a few party providers and one guy in particular I have come across and met 3 times who 'manages' multiple profiles of girls and couples who meet in travelodges around London, taking the bookings and coming to the lift while the girls fuck their way around the room.
Weekday afternooms/early evenings.
Look on fabswingers for meets in greater London that refer to 'hotel contributions' (I've paid £50, £40, £50)
Only thing to warn is don't set your sights on the women being too young, slim or beautiful. Enthusiasm goes a long way for me though, including DFK with all 'lovelies' I've met.