Hi, nostalgiackh,
I am continuously surprised at the amount of film and audio tape available in the Glen fan world.
Some of these recordings go back to the sixties.
The discovery of most early recordings was serendipitous. The most amazing one that I am aware of is film or tape discovered in a trash can in Hollywood by a fan: The Making of Norwood (1970). Norwood was Glen Campbell's second studio film in which he starred. The lucky finder, a most generous and loyal Glen fan, had this film transferred to DVD and then he posted it on YouTube (only for VideoBeat.com to allegedly download and sell it on their website).
Shindig! episodes (Sonny & Cher appeared on this program) from the mid-sixties are still available, one of the few early rock shows that preserved tapes or film.
Other sixties shows were not so fortunate. I believe that all of Hootenaany's film was not preserved by the network on which it aired. However, mysteriously a 1963 promo of this show is posted on YouTube.
Also, I read that an uncle of one of the Hoot performers shot film of the show when it was broadcasted on television using Super 8 film and then later converted it to VHS video! No audio, however. Still, a treasure because it captured a folksinging group at or near the beginning of their career.
The performance of Cher with David Bowie from the "Cher" show is still around. Here are 6 minutes of highlights:
https://www.youtube.com/watch?v=_z9b0GFRz9g" onclick="window.open(this.href);return false;. This clip looks like a homemade job, you think?
This clip from "Cher" is better quality:
https://www.youtube.com/watch?v=yvJVQYLlj2A" onclick="window.open(this.href);return false;
Here's another clip that appears to have been recorded from a "Cher" show:
https://www.youtube.com/watch?v=U0Gw9IUmjwM" onclick="window.open(this.href);return false;
Also a goodie from "Cher" in 1975:
https://www.youtube.com/watch?v=uFHm6vKjO4Q" onclick="window.open(this.href);return false;
You have likely seen all of these YouTube clips. Perhaps all of these YT clips are from the rebroadcasts on VH-1? Have you contacted the owners of these YouTube channels to find out if they have complete episodes including the 12/14/75 one? Just a thought.
A 17-second audio of a promo for the very show you are seeking is on the net. Perhaps Cowpoke can post it in the Hitching Post forum for all fans here to listen to -- a quip between Glen Campbell and Cher! Priceless!
IMO, the sharing of these early gems is contingent on the generosity of its "owners", their ability (or access to techies who know how to make these transfers in the best way possible) to transfer the early media to a contemporary medium, their desire to do so, their awareness of the value of the recordings in their possession, and, of course, copyright laws!
You had mentioned that 1975 was not a good year for Glen Campbell. It was also not a good year for Cher, right? She and Sonny had broken up, their divorce was in all the tabloids. Perhaps the "Cher" show reminds Cher of an unhappy time in her life and this is why she has not been behind the release of her "Cher" episodes?
Dee