looking for something for my gravel bike that means I can easily ride in normal shoes for popping to the shops, or a quick lunchtime spin etc. without changing pedals.
Do they work?
I've got some on my gravel bike for the same reasons. Perfectly happy with them. Much better than the XT Trekking (older version without the pins) that I had before.
Which way do they tend to hang? Cleat side up or flat side up?
They tend to hang in such a way that with SPDs you approach from the rear slightly below to engage and with flats you approach from the front slightly above if that makes sense. Doesn't take much thinking about after the first couple of rides.
I have a set on my hardtail. I like 'em. They hang just like infernocup says. They might be a bit stiff at first and not hang so well, but after a few rides the grease loosens up a bit and then they return to that position more easily.
Worth noting they come with multi release sm-sh56 cleats rather than a pair of single release sm-sh51.