My feeling is that John Doe is an employee of a harp company, or perhaps a relative who hears the gossip, or a technician. Not too many other people hear or care about the details of what is made where and odd harp stories.
Mel, “Noises Off” is a farce about the on-stage and back-stage antics of a theater group. One of the props in the play is a plate of sardines which is constantly mishandled and mislaid. If you ever have a chance to see the show, it’s incredibly funny.