This is now fixed following the upgrade to Mesa 18.3.6 so it looks like my bug might be associated with this, "AMD Raven hang during va-api decoding";
https://bugs.freedesktop.org/show_bug.cgi?id=109648 Happy for this one to be closed.
- Bug#920307: kodi: Kodi crashes when attempting ... Vroomfondel
- Bug#920307: Acknowledgement (kodi: Kodi cr... Vroomfondel
- Bug#920307: Acknowledgement (kodi: Kod... Bálint Réczey
- Bug#920307: marked as done (kodi: Kodi cra... Debian Bug Tracking System
- Processed: Re: Bug#920307: Acknowledgement... Debian Bug Tracking System
