[DaveBlake]

I note that when deleting scan paths from within Kodi and ensuring they are also no longer in sources.xml, on a scan Kodi will still insist on scanning the deleted paths.

You don't say how you go about "deleting paths", it sounds like you did something manually. But anyway Kodi was designed for use with removeable sources e.g. on USB stick, so the scanning of library update does not check if the sources are available or even if they are still listed in sources.xml (or in the sources table).

Library update looks at the list of paths for the music it has previously scanned into the library. If you have removed a source and no longer want the related items in the music library then you need to go to System Settings > media > library and clean the music library https://kodi.wiki/view/Settings/Media/Li..._library_2 Be carefull to scroll down to the music section, it is easy to mistake and clean the video lib instead.