Do they still exist? When I lived in London, if you were single, available and in a supermarket on a Tuesday evening, you'd carry a hand basket with some unusual item prominently displayed, like a giant bar of chocolate. I think there was some sort of code with different items signifying god-knows-what. I moved to Lincoln about five years ago and it doesn't seem to be a "thing" here. Or maybe it's a different night. I'm not going to wander around Sainsbury's every night without buying anything just to find out... I'd look like a stalker. Perhaps I should reintroduce it somehow. What subtle clues would you use to advertise your availability? Something unusual enough for people to notice but not weird enough to freak out the security guards. Like sunglasses on your head when it's dark outside. Or carrying pork sausages while wearing a yarmulke?