This is very obviously a soundboard tape, not an audience one, so what the previous reviewer was listening to I have no idea. It's 'official live release' quality.
I'll come clean- I was involved [unpaid] in several of these releases. They were named the Collectors Series- for a reason. They were 'official bootlegs' for the Martyn collector/completist- great performances, fair sound quality, reasonable price, and Voiceprint, the label, paid John (not a rich man) good royalties on them.
I wouldn't recommend them to the casual buyer or beginner but that's not who they were intended for.
This is a good example of where John Martyn was in 1986- full band, plenty of keyboards and sax, quite slick and smooth readings of a mix of his 'classics' and newer material, some of which was unreleased at the time and would end up on 1990's The Apprentice. Not my favourite Martyn period personally but always worth checking out.