Hah! I recorded the show you are referring to. It wasn't even to tape, it was to MiniDisc - my flatmate at the time had a MiniDisc "walkman". The mic was something I borrowed from my work, which was designed to be mounted into a roof to record speech in a small room. And yes, the batteries ran out before the end. But I suspect it's the best you're going to get.
I wanted to see the "soundcheck" so I turned up around 1pm along with the selected members of the Band of Strangers. I just hung out in the lobby. There was a TV crew around and they wanted everyone to sing along with something, so I'm actually on tape somewhere - I've seen it, I'm in a South Park t-shirt - where I have no right to be!
Everyone got walked backstage after a while and Neil came out to meet everyone, find out what they played and where they could fit in, etc. I stuck around in the background and after a while, I just went and sat in the empty theater to watch the songs being worked out.
I remember the show itself being quite underwhelming. I trust your memories of it are fonder.