Just to update re. Cambridge Audio CXN v2 & Tidal.....as per above it still works, but no longer via Tidal app....
Further communications between me and Cambridge reveal the connection between them and Google is Chromecast itself (I was a bit slow on the uptake). So they are 'working' with Google to sort the latest codes since Tidal updated their app. Why there was some change from Tidal's end is a complete unknown. This update due in the very near future. Cambridge couldn't be time specific claiming it was out of their hands.
Further, because their new Edge NQ network player is Roon ready, there is a strong possibility CXN v2 will get the same treatment, once the tech filters down. However, there were no immediate plans to make it happen. I was told as it's Roon capable (via Chromecast), it is not foremost on their engineer's minds. Perhaps early New Year was the best they would tell me.
To compare this unit with the Volumio Primo, I've not heard both side by side. However, Chromecast is important to me and that would be a deal breaker. Also, they are in different price brackets. CXN vs roughly 700 pounds I believe. Given I'm not in Europe I could be wrong about that.