HEOS app not displaying folder art

[Nothung]

Hi I am having a problem displaying folder art on the HEOS app which I am using since ugrading my Synology NAS to DSM7.
My music is organised into folders - Classical, Jazz, Opera, Rock & Pop etc which contain Artist folders then Album folders and there is artwork at each folder level.
The artwork displayed fine using Kazoo as an OpenHome control point though I often had to reload the app.
The HEOS app ignores my folder art and only shows artwork when I drill down to album level. DSaudio shows the artwork for each level but is quite slow to load.
I have tried using the indexArtwork feature but it doesn't change how the HEOS app works or perhaps I have not understood what is required and not set it up correctly. I also don't see TagViev and have tried following Simon's suggestions in another thread without success.
If anyone has got indexArtwork or TagView to work with the HEOS app and can help by posting a step by step guide I would be most grateful.
Regards