Tvheadend

Hi all,
I have a strange issue with my tv headend setup.
Firstly everything works as expected show are recorded as expected.
I save the recordings to a folder on my nas so the recorded content is available to kodi devices.
The recorded show list is populated as the recordings are made.
If I restart the tvheadend unit the list of recorded shows is wiped. The content is not actually lost as its still available from the nas it's just the recorded shows list which is lost.
Any ideas. I would have assumed tvheadend would read the recorded list from the db and rebuild the list after the restart was complete. I'm not sure where the recorded show list is stored - seems to be in Ram and not on the disk.

Tvheadend is running on a raspberry Pi 3+ the latest version is installed.
The operating system is openelec latest version

Thanks
Julian