Re your question DRaftervoi -

"As for the Bowie/mono issue:  could it be that the circulating show was sourced from a cassette tape recorded by a fan, rather than a radio station reel, or a soundboard?....Do you know when the BBC began broadcasting in stereo?"

The BBC apparently did their first stereo broadcasts I think as one channel through the radio, and one through the television. I remember now, there was a very early broadcast like this by The Rolling Stones, around 1965, it featured Route 66 on it.

As far as I know, for rock music  - at least live sessions and concerts, I don't think stereo was used much until the early 70's either.

As for the item in question - a John Peel In Concert broadcast from 1971 - the existence of a stereo version was practically unheard of. For years not just a mono version, but a very muddy one indeed had been in circulation, or at least 'average' as quality goes.

The stereo version has emerged from a very rare BBC Transcription LP, 'Pick Of The Pops'. One side - the mono side - ironically has some hits of the day on it (not big hits though...I say ironically as they would have been recorded and pressed on stereo records in general), while the stereo side has six of a total of eight tracks that made up a concert Bowie played in the BBC studios in 1971.

The full recording features Queen ***, Bombers, The Supermen, Looking For A Friend, Almost Grown, Kooks, Song For Bob Dylan, Andy Warhol, It Ain't Easy.

Bombers and Almost Grown are missing from the stereo version.