Thanks for the responses guys:
Friedmett - Chris (medogsfat) lent me a MMC 20S that confirmed that the Beogram is working fine, it's just my MMC 20EN that has dropped a channel. Thanks for the offer though :)
Andy - I've been persuaded to go down the Soundsmith route, though I might be un-persuaded if I could try your CL. Are you sure that you won't mind if I decide that I don't want it? I'd cover postage costs both ways.
President, Beomaster 8000 Appreciation Society