Just found, probably years after everyone else, the BBC's Peel's Festive 50s. With 31 seconds (probably a licensing fair use thing) of almost every track.
I was actually trying to find the song Venceremos, off the album Working Nights by Working Week and there it was number 50 in 1984. Singing on the track were Tracey Thorn and Robert Wyatt. What more is there anyone could want?
And now I find they've reformed (well, they had in 2005 and I've only just found them again).