Funeral Mariarchi (SGC's final album, btw) and a whole bunch more are available directly (and to listen to) from Bandcamp:
https://suncitygirls.bandcamp.comHey, there's even an Uncle Jim album there (another Alan Bishop alias, as seen in several of the film posted earlier).
I'd recommend to definitely check out Alvarius B's Baroque Primitiva from that list, which consists mostly of Ennio Morricone "covers", alongside three originals plus a versions of John Barry's You Only Live Twice and Brian Wilson's God Only Knows.
Also worth mentioning (as Ennio's name has popped up) is the compilation curated by Alan Bishop of Morricone originals entitled Crime And Dissonance - featuring cuts from his non spaghetti-or-hollywood scores.