On another thread I was surprised to find that many Anonimo owners have had watchmakers refuse to attempt repairs on their Anonimos. If you are in the U.S. Chris at Wilson Watch Works can repair Anonimos and is able to replace Anonimo unique parts when necessary. Below are photos of a recent Anonimo repair he did where he fitted replacement parts. The crown does appear to have a coarser ridging and the helium valve is a little different, but the watch was presentable enough to be sold to a collector. The thing about Wilson Watch Works is that they actually manufacture watches and have appropriate equipment like precision drill press, lathes etc.
This is a link to his website: