Thank you. There is indeed and I had noticed that before but I had not noticed that there is ANOTHER browse media button on that pane. So the workflow to add music is…
On the Sonos card press favourites (actually called Media Browser in the settings)
On the favourites card press browse media
On the subsequent now playing card press browse media
Choose your media source and select your music to play.
Is it just me or is this a bit long winded for something I would want to do on a regular basis. Surely a browse media button right on the front of the card (ideally configurable to take you direct to your media server of choice) would be most valuable? Maybe my workflow is different to ‘normal’ people 
And then there is the question of how I play a whole album from my DLNA server not just an individual track (works ok using the Sonos Music Library tile) but that is not a Sonos Card issue so I will leave that for another day and another place.
That’s actually ongoing work. So, if you feel brave, try out the beta and play around and see what you think:
Make sure to read the breaking notes.
PunxaPhil
This looks awesome! Do you have a screenshot of your now playing section or the full card-mod style code? Thanks!