I think you can only use them with a Maillard hub because of how they fit not sure though. Try sending stidds a pm, even though he's Welsh he knows his stuff when it comes to this type of stuff
Welsh, cheeky fooker.
They are relatively rare hubs, the helicomatic freewheel can (as Ash says) only be used with Helicomatic hubs due to the fact they do not have a thread on the hub/freewheel, they have a twisted spline setup.
Very nice hubs and freewheels though, they were standard on Yamaha's (and I have them on my Yamaha) and some Peugeot's BITD.