No trace of the big click in WLL (drum roll just before Everybody Needs Somebody).
None of the errors that have been mentioned in Dancing Days.

Presence a mis en ligne deux morceaux complets du multipiste de Southampton 73. Un show inconnu dans une qualité sonore parfaite, c'est pas désagréable

Although the keyboard sound in this passage does not come across all that clearly on the LA and Long Beach bootlegs, there's no doubt at all that the notes, and the instrument on which they are being played, are utterly different from what has appeared on the official release. The guitar and vocal parts on "How The West Was Won" are unmistakably from Long Beach '72, so the obvious conclusion is that John Paul and/or Jimmy didn't like the keyboard part on the original recordings and decided to replace it. But how? Had Jonesy brushed a few years' worth of dust off the mellotron, or an even thicker layer of dust off those old recorders, and laid down a completely new part in the studio? That was a possibility, but not a particularly realistic one.

In the 2005 edition of The Concert File, Dave Lewis and Simon Pallett provided the following information concerning the show at Southampton University on 22nd January, 1973: "Tonight's show ... was professionally recorded on Page's instructions. ... In 2002 Page salvaged the tapes for this show for consideration for release for what would become the How The West Was Won official live set. Engineer Kevin Shirley did mixdown some of the performances from this show for possible use but ultimately they decided to issue the 1972 Los Angeles and Long Beach recordings." Armed with this information, it wasn't too difficult to make an educated guess at where the "Stairway" mellotron part on "How The West Was Won" had come from.