Restriction of BBC Radio HLS/DASH to authorised third parties

[FakePlasticDunk]

"Cadence recognises the downloaded file as aM3U playlist, but when I open it all the station addresses are greyed out and can't be selected."

This makes me think that your Cyrus might not allow the playing of internet radio streams from a playlist, which is also the case with my Cambridge Audio NP30. With the NP30, we got around this by using the unit's web interface to directly enter and save stream URLs to its internet radio presets. Is that something that is possible with your Cyrus, either via the Cadence app or a web interface? Cambridge Audio's tech support were helpful in working some of this out. If the Cyrus won't play streams from a playlist, and there's no way of saving URLs to internet radio presets, you might be out of luck.