By adding the extra source in the 861v8 config solves all on/off issues running the 218 in between.

I have now loaded the latest firmware to the 8000SE. I have tried to connect using the digital out from the 218, but just couldn't get the comms going between everything so I have given up.

Lounge: 861v8 with ID41, 218, UHD722, Sonos Connect Wyred4Sound, AppleTV, Oppo 105, DSP8000SE, DSP5200SE
Streaming: Roon/Spotify
Currently not in use: DSP5200 x 2 pairs, DSP5200HC, DSP3200, 218 x 2, MS600, DSW x 2, MC200, Sonos Connect Wyred4Sound