Sorry for the delay getting back - been working away.
It's a Pace 1000, ex c&w and we're on the purple CR3. Still can't switch it off using either the power button on the front or the remote. Just checked the card and as soon as I opened the flap got the "mute card" error again. Still also got no RGB output
Card itself looks OK - a little yellowish at the chip end but certainly not burnt or cracked. Took card out and gave it a wipe but it was nice and clean anyway and firmly pushed home too.
I think a call to faults is in order - I'm missing my RGB and I fancy one of those new Samsungs anyway!