LF,
These are not difficult to manufacture yourself.   Hobby Lobby, Joann’s, and many other hobby-fabric stores sell belt leather that you can scribe and cut, dye, and wet-mold guides to match.  You can stitch and glue the leather around the brass.  Weaver, Tandy, and Amazon sell all sorts of stitching or pricking-chisels to match the original as well as  harness-saddle needles and thread.  There is a YT, many years old, that features and English artisan restitching an old leather brief case. Takes some time but good for these Winter days.  Patience, for me, is the key.