Apologies in advance if everyone thinks this is obvious, but it may prove useful to some people. I have realised that the 'rename' facility gives me total control over the order in which my favourite playlists, radio stations etc display. So, for example, I have about 50 Sonos Playlists. I have selected 15 that I play most and added them to the 'My Sonos' Playlists category. Then the eight 'favourite favourite' playlists I have renamed with an asterisk in front of the name, so that these are the ones that appear without my having to tap "See All".
I have also put this list at the top of the "My Sonos" screen, as I use Playlists more than radio stations etc
I can see other possibilities here for categorising items, but I'm still playing around with this.
For the avoidance of doubt, the name change only affects the item in My Sonos, not the original source.
I hope that is of some use.
All we need now is icons a sensible size.....