oops! sorry Joe

Definitely Joe singing By You. - FLS

Does Jerry Busher sing By You? because before the song, Ian introduces him. If so, I’d assume this is because nobody would be able to hear Joe as he is a kinda laid back singer.

Well, since World Beat also gets played on atleast one more occasion (see the following night), now I know that it's not a one-off improvisation...

First off, this is a great sounding recording yet the guitars, bass or even Ian's voice do sound a bit muffled in the mix sometimes; still, Guy's voice sounds particularly close and crispy clear all through the set which results in, for instance, an awesome version of Fell, Destroyed.
Other than that, note that the set list features World Beat. It is a song I have never heard before, and as of yet I still do not know if it is a one-off improvisation, some sort of cover song or a proper Fugazi song that has never left the drawing board.
Other highlights for me personally include an early première of Caustic Acrostic, Fell, Destroyed into Birthday Pony into Downed City (these transitions are flawless) and a tremendous spun out rendition of Version into Cassavetes (another seamless combo).