Hi -- I don't know about any Portsmouth Sinfonia albums,
but i have a cd "Dead Parrot Society -- the best of british comedy".
It has a few P.S. tracks: Also Sprach Zarathustra, William Tell Overture,
Pinball Wizard (live), Classical Massacre (P.S.'s rebuttal
to hooked on classics).

Most of the disc, though, is skits by british comedians.
A fair dose of Monty Python (The Courtroom ("You know, the Cole Porter
that wrote Anything Goes"), Crunchy Frog, the Argument Clinic, Lumberjack
song), and stuff by others (Peter Cook, a Dudley Moore song (one that
isn't too hot, actually), and others i hadn't heard of.  A couple of
John Cleese 'solo' skits which are great.)  My evaluation: most tracks
are worth a few smirks, a few are duds, and a few are *hilarious*.

Anyway, am selling it for $9ppd (if you are in U.S.), let me know
if interested, or if you want a detailed track listing.

By the way, according to the (extensive) liner notes, the Sinfonia was started
by a group of students at the Portsmouth school of art; however it
was brian eno that produced their first album.