Hi Ian,
try this method:
1) remove all network mounts present in Sources section.
2) login with ssh into RuneAudio player.
3) enter into the network mounts root directory.
cd /mnt/MPD/NAS
4) remove all the unneeded directories.
rmdir Music
rmdir Library
rmdir Music Library
5) go into Sources section and start MPD REBUILD LIBRARY. (it will take seconds because you have no mount points active).
6) recreate your network mount point.
Bye.
Simone.