Ingestion of .lrf files (newbie questions)

[freddieFishCake]

Hi,
I recently installed CWA and ingested my previous CW library via the ingest folder to ensure a nice clean database.
About 600 epub files ingested nicely, but .lrf files were just moved to the config/processed_books/failed folder.
I read the documentation and added lrf to the list of allowed file types in basic configuration / feature configuration/ allowed upload formats and re tried an lrf file but same result.
Restarted the container, checked configuration still contains lrf and retried, failed again.
I then opened a terminal in the container and checked that a command like
$ ebook-convert book lrf book.epub
works, it did and I could subsequently import the epub into CWA in the normal manner.

Am I missing something obvious to enable automatic conversion in ingest?
Thanks for any hints or tips!