Can't reset Favourite artwork/restoring deleted Favourites

Wow - loving the update!

One small gripe. Used to have favourites folders for Films, TV and Kids Films. Deleted the Films and TV one as Infuse now has those. Still want to keep my Kids Films one though, but can’t delete the artwork I set for it. Deleted the PNG from my NAS, tried the reset option, even restarted the ATV. Any ideas?

Also - how do I restore a Favourite that I deleted?

Thanks!