The limited animation sequence was re-used in a 2007 episode of Panorama also dealing with Scientology, and again in a 2010 episode. I do not have details on who made it.
"The upper-level courses are called OT, which stands for 'operating thetan', Hubbard's word for the spirit. The OT levels are supposedly so powerful that you can die of pneumonia if you are exposed to them unprepared."
"It costs around £5000 to take OT III, which contains Hubbard's cosmology. The church has tried to keep this material secret, but former senior scientologists in America have leaked it and versions have been published. This is an outline of the story."
"Seventy-five million years ago, this planet was called Teegeeack. There were ninety planets in this sector, called the Galactic Confederation." ("This is part of the text of a Hubbard lecture", adds a different narrator)
"They had elected a fellow by the name of Xemu to the supreme ruler, and they were about to unelect him."
"And he took the last moments he had in office to really goof the flute. Xemu decided to take radical measures to overcome the population problem."
"Beings were captured on other planets and flown to locations near ten volcanoes or more on Earth."
"H-bombs were dropped on the volcanoes, destroying the bodies of the beings who, as thetans, attached themselves to one another as clusters."
"A revolt followed of the loyal officers against Xemu."
"Xemu was locked up in an electronic modern fortress and remains there still. Since that time, beings born on this planet have had clusters of thetans attached to their bodies. OT III can run-out these clusters and cause them to leave us and reincarnate as individuals."
As an aside, this could well be the first ever visual depiction of Xenu. A brief Google image search shows that, aside from the South Park interpretation, his current image in popular culture is of a grey alien wearing Ming the Merciless-esque robes, so Panorama's version is somewhat unusual - although it did recently inspire a cuddly toy.