After some struggling, Filezilla suddenly started to work and I copied the debug log file across.
The file is huge and is pretty hard to read.
But I managed to thin out some typical scanner errors (sometimes there are 12 log lines per file):
1) 2020-04-09 19:45:14.366 T:3953283968 DEBUG: VideoInfoScanner: Could not enumerate file smb://192.168.1.3/vol1/TV/Bagpuss/Bagpuss - 02 - The Owls of Athens.avi
2) 2020-04-09 19:45:17.614 T:3953283968 DEBUG: VideoInfoScanner: Scanning dir 'smb://192.168.1.3/vol4/Music Videos 3/Pere Ubu/Pere Ubu - Modern Dance DVD-A/' as not in the database
3) 2020-04-09 19:45:16.728 T:3953283968 DEBUG: VideoInfoScanner: Skipping dir 'smb://192.168.1.3/vol1/films/Brave 2012 720p BluRay DTS x264-MgB/' due to no change (fasthash)
4) 2020-04-09 19:45:22.294 T:3953283968 DEBUG: FindMovie: Searching for '3 Minute Wonder - Microsoft Babies (Week 2)' using The Movie Database scraper (path: '/storage/.kodi/addons/metadata.tvshows.themoviedb.org', content: 'tvshows', version: '3.5.2')
2020-04-09 19:45:22.330 T:3953283968 DEBUG: scraper: CreateSearchUrl returned <url cache="tmdb-search-3%20Minute%20Wonder%20-%20Microsoft%20Babies%20(Week%202)-en.json">https://api.tmdb.org/3/search/tv?api_key=6a5be4999abf74eba1f9a8311294c267&query=3%20Minute%20Wonder%20-%20Microsoft%20Babies%20(Week%202)&language=en&append_to_response=credits,external_ids,images&include_image_language=en,en,null</url>
2020-04-09 19:45:22.331 T:3953283968 DEBUG: CurlFile::Open(0x2670250)
https://api.tmdb.org/3/search/tv?api_key...en,en,null
2020-04-09 19:45:22.349 T:3953283968 DEBUG: Get: Using "UTF-8" charset for "https://api.tmdb.org/3/search/tv?api_key=6a5be4999abf74eba1f9a8311294c267&query=3%20Minute%20Wonder%20-%20Microsoft%20Babies%20(Week%202)&language=en&append_to_response=credits,external_ids,images&include_image_language=en,en,null"
2020-04-09 19:45:22.351 T:3953283968 DEBUG: scraper: GetSearchResults returned <results></results>
2020-04-09 19:45:22.352 T:3953283968 DEBUG: FindMovie: Searching for '3 Minute Wonder - Microsoft Babies (Week 2)' using The Movie Database scraper (path: '/storage/.kodi/addons/metadata.tvshows.themoviedb.org', content: 'tvshows', version: '3.5.2')
2020-04-09 19:45:22.352 T:3953283968 DEBUG: scraper: CreateSearchUrl returned <url cache="tmdb-search-3%20Minute%20Wonder%20%20%20Microsoft%20Babies%20(Week%202)-en.json">https://api.tmdb.org/3/search/tv?api_key=6a5be4999abf74eba1f9a8311294c267&query=3%20Minute%20Wonder%20%20%20Microsoft%20Babies%20(Week%202)&language=en&append_to_response=credits,external_ids,images&include_image_language=en,en,null</url>
2020-04-09 19:45:22.353 T:3953283968 DEBUG: CurlFile::Open(0x2670250)
https://api.tmdb.org/3/search/tv?api_key...en,en,null
2020-04-09 19:45:22.379 T:3953283968 DEBUG: Get: Using "UTF-8" charset for "https://api.tmdb.org/3/search/tv?api_key=6a5be4999abf74eba1f9a8311294c267&query=3%20Minute%20Wonder%20%20%20Microsoft%20Babies%20(Week%202)&language=en&append_to_response=credits,external_ids,images&include_image_language=en,en,null"
2020-04-09 19:45:22.381 T:3953283968 DEBUG: scraper: GetSearchResults returned <results></results>
2020-04-09 19:45:22.381 T:3953283968 WARNING: No information found for item 'smb://192.168.1.3/vol1/TV Shows 3/3 Minute Wonder - Microsoft Babies (Week 2)/', it won't be added to the library.
Is there a guide as to what all these errors mean?