A lot of the available footage and recorded stuff from Zeppelin's live stuff is sloppy. Often off tempo too. But like the "Minnesota Blues" (mess of the blues) medley on this BBC album, even amongst the sloppy stuff there are jewels to be found.
By the way, I am assuming this double album I have is bootleg. It does have the record company info on it but the album cover is basically a cartoonish picture of a cassette tape recorder. I'm also assuming it was recorded on cassette from the BBC broadcast and then cut onto vinyl. The sound quality isn't great.
Both times that I saw Plant the shows were incredible. What struck me more than anything else was that he seemed to be having the time of his life....playing for a crowd in Columbia, SC. I could not, and still don't understand how the god of rock and roll was having fun playing yet another show on the road in my humble home town. I came to the conclusion that he is either an incredible actor/showman or he was actually enjoying himself. I suspect it was probably both.
Either way, when the performer is performing well AND having a good time, well, that makes for a great show.
The second time I saw him he played several Zep songs. Brought the house down.