updated to kernel 5.17rc8 (needed for another bug I raised) and downloaded version 1.9.3 of intel-signed sof-adl.ri from the SOF Project (
https://github.com/thesofproject).
The sound is now recognised, I can hear audio - when "test right" is played no audio is observed, when "tet left" is selected both speaks appear to work - so its working, but not quite.
Who is responsible for packaging the firmware-sof-signed package? looks like it needs updating.