On May 8th, 1969, BBC Radio's David Wigg went to Apple Corps to interview John and Yoko. 12 minutes of his interview was released on the 1976 LP The Beatles Tapes with David Wigg, but none of the material discussed the ostensible reason for the chat: John and Yoko's new album, released the following day, Unfinished Music No. 2: Life With The Lions.
Well, here is a previously unreleased extra four minutes of Wigg's recording from that day which rectifies the problem. John seems overly optimistic about the sales potential for his experimental albums: