I swiped the wrong command name, I've corrected it now. But if the metadata.opf files are not being progressively updated what else could be slowing down the OPs updates?
@
kjdavies - have you tried compressing/vacuuming the library databases, there's a tool in Jobspy/Utilities that will do all libraries that calibre knows about except the current one, so I run it from an empty library.
BR