Hi brifletch, in case the smbd is still dying: If you want you can also try the steps I suggested in this post Update fail due to samba, now samba is down - #2 by JimKnopf
Prefetching a similiar result if would be also fine to see what is in your cache directory
ls -al / paste-log
ls -al /var | paste-log
ls -al /var/cache | paste-log
ls -al /var/cache/samba | paste-log
ls -al /var/cache/samba/lck | paste -log