Henry Cow - Legend (1973)
I don't know this album so well, but I'd like to and that's basically why I suggested it. What I know so far is that it's the debut album of Canterbury/Avantgarde band Henry Cow. Supposedly, the Canterbury sound is more prominent on this one than it is on their later albums. Like many other Canterbury acts like Gilgamesh, Isotope or In Cahoots, this is supposed to be a somewhat jazzy and largely instrumental affair. It's also supposed to be quite good!
So there you go