The Pizza Express' outlet where they were recorded would be the one in Greek Street, Soho, where there is a basement jazz club. Very good it is too !
Original owner Peter Boizot was a big fan of jazz - and opened the club back in the 1970s. In the 'earlier' days it featured mainstream groups such as Scott Hamilton, Ruby Braff, Al Cohn etc. Last gig I caught there (some years ago) was by Kenny Garrett.
This one (issued by the chaps at Mole Jazz) was recorded at Pizza Express:
There's still good jazz featured there too. Charles McPherson was featured last week, I believe.