Thanks everyone for the input so far.

I popped into the local Comet and the very nice assistant allowed me to play with their demo instalation so now I know what audio settings are available. Both Dolby Digital and PCM stereo are there so both my setups (MC and 2C) should work.

Onto my two-channel set-up, I have been experimenting with the HD621. The link above was very useful and it has saved me from a rabbit-hole full of gotchas especially using D1 for the output instead of D2 which is what multichannel demanded when I tried it. I have discovered that the HD621 can be activated (by pressing the source buton) without lighting up the full system, even with comms connected, so that looks like a solution to allow domestic bliss to prevail.

I do have an obscure question, however. If I set the Audio output to Video/HDMI (needed to feed the telly when the system is off), will I still get audio on the D1 output for when the system is on?

TIA

In the spirit of Spinaltap, I would like to confirm that I am not involved in the corrupt theft of a global sport.