Did anyone ever see these "leather retention straps" used in service that a few UKicon dealers now have for sale. According to the people selling them they were used to help retain No4 spike bayonet scabbards in frogs that were "a bit loose". One could imagine finding that one had lost one's bayonet when one needed it if the scabbard wasn't securely retained to the frog. On the other hand they may have been produced but never issued, hence why some are available now.