Let's see, where were we...
Oh yes! John Lennon was in the first stage of a massive media campaign promoting his new album, Walls And Bridges. The first single, "Whatever Gets You Thru The Night" came out September 23rd, 1974 in the US, with the album following a week later. On September 21st, John traveled from Los Angeles to San Francisco and stopped by KSAN-FM to appear during Tom Donahue's evening shift.
In addition to plugging the album heavily, John played a number of songs by other artists, old and new, often to illustrate a musical point or highlight some of his newer favorites. During the three-hour show, John talked about the title and cover art of Walls And Bridges, his work with Phil Spector, his invitation by WNET to introduce Monty Python's Flying Circus, the deportation case, George's upcoming tour, recording Sgt. Pepper, Doc Pomus, and the Maharishi.
Speaking of George, back in England he was busy starting up his new record label, Dark Horse, officially launching the project with a press conference on September 6th. He had begun to record his solo LP of the same name back in the winter of 73-74, but most of the sessions took place in a rushed fashion during August and September amidst other projects.
The most important to George was producing an album and arranging a concert tour for Ravi Shankar and a host of Indian musicians. His home studio, FPSHOT, was used to record the LP Ravi Shankar's Music Festival From India (eventually released by Dark Horse in 1976), as well as being a base for tour rehearsals.
On September 23rd, the concert at London's Royal Albert Hall was filmed by Dark Horse, with George present to introduce the proceedings: