Another thing I discovered is that Spinal Tap's Stonehenge gag might predate Black Sabbath's.
This is Spinal Tap was released in March 2, 1984. Black Sabbath's Born Again tour started the August 7, 1983 and ended the March 4, 1984.
But given the production time of a movie, the Snonehenge in Spinal Tap scene was probably shot several months before.
Dangerousminds.net discuss this in the article Life imitates comedy: Spinal Tap uncannily anticipated Black Sabbath’s very own Stonehenge debacle .
Black Sabbath’s (. . . ) incident with the Stonehenge set didn’t occur until around October 21 (1983), when they hit Montreal. It seems unlikely that they hadn’t finished principal photography on This is Spinal Tap by then (the project had already been kicking around for a while), and nothing about the Stonehenge gag suggests a rush job — a full song was composed, a live rendition was recorded, and so forth.
When This is Spinal Tap was much closer to the pitch stage, Rob Reiner and his three principals, Christopher Guest, Michael McKean, and Harry Shearer (who did the bulk of the writing), put together Spinal Tap: The Final Tour (part 1, part2), a 20-minute rough cut of the movie that they could show to financiers as an example of what the end result would look like. This footage dates from 1981 or 1982 — well before Black Sabbath released Born Again — and the Stonehenge bit is there pretty much in its entirety.
Now on the Stonehenge incident Geezer Butler said in an interview with Classic Rock Revisited with Jeb Wright in May 2005:
Jeb: ( . . . ) My source gave you the credit for the whole mistake.
Geezer: It had nothing to do with me. In fact, I was the one who thought it was really corny. We had Sharon Osbourne’s dad, Don Arden, managing us. He came up with the idea of having the stage set be Stonehenge. He wrote the dimensions down and gave it to our tour manager. He wrote it down in meters but he meant to write it down in feet. The people who made it saw fifteen meters instead of fifteen feet. It was 45 feet high and it wouldn’t fit on any stage anywhere so we just had to leave it the storage area. It cost a fortune to make but there was not a building on earth that you could fit it into.
Jeb: Where is Stonehenge now?
Geezer: I last saw it on the docks in New York on the same tour.
Jeb: So somewhere these things are around.
Geezer: They were probably thrown into the Atlantic Ocean.
Jeb: One day a futuristic society will find them.
Geezer: They will think it is Atlantis.
On the other hand, Ian Gillan accuses Geezer Butler on this interview with Mojo Magazine in December 1994:
We were up at a company called LSD (Light and Sound Design) in Birmingham, and the lighting engineer asked if anyone had any ideas for a stage set. Geezer Butler suggested Stonehenge. “How do you envisage it, Geezer?” asked the engineer. “Life size, of course,” replied Geezer. So they built a life-size Stonehenge. We hired the Birmingham NEC [National Exhibition Centre] to rehearse in and they couldn’t get these bloody things in there.
We opened in Montreal and Don Arden had hired Maple Leaf ice hockey stadium for a week, so they shipped the set over there and could still only get a few of those damn stones up, one each side of the stage, one behind the drums and two cross-pieces.