The title of your subject unfortunately reminded me of when I worked at an Adult "toy" store, 30 years ago....
Could it be a different lego mold? Or a lego "cousin"?
Graham, at a glance, those look like a small version of Wookie cuffs, or `binders" as SW geeks call them.
I wondered if there was an alternative word for handcuffs, but trying 'binders' on Playmodb only came up with books in which papers, magazines, etc. are bound together.