Thanks Andrew!

I’ve updated both my transformers and got Spotify Multiroom to work on the third attempt. I was initially playing music through the multizone on my first attempt to switch in Spotify. I ended up with the music I was playing overlayed with the Spotify music. Rebooted the transformer, recreated the group and then I got multiroom Spotify but the zones were out of sync by over a second. Lastly I switched which transformer was the group master and boom!!! Multiroom Spotify in all its glory!

Very important feature added.
Much appreciated!