You might be interested in this Newsnight report on the English National Opera's 1981 Tristan.
"Newsnight: "Tristan and Isolde"; Reginald Goodall, Alberto Remedios, Linda Esther Gray"
Post by Nicholas G
I think the Parsifal is stunning. I was actually at that Prom and would love for someone to release a recording of the whole act 3.
It has already been "released"-though not officially. It can be bought here: