Rosemary Ann Sission's early Black Cauldron scripts

 Hello again.  

 Rosemary Anne Sission, "the Miss Marple of British playwriting" wrote scripts for Disney live-action films as Escape from the Dark (aka The Littlest Horse Thieves 1976), co wrote the script for Freaky Friday (the 1976 Jodie Foster one) and the Watcher in the Woods (1980) with Bette Davis. 

Rosemary did script treatments for The Black Cauldron going back to the 70's. 

images from Heritage Auctions. 

                                         one of the working titles: "Taran and the Horned King"

                                                   

another script here on this link at heritage auctions

  The Black Cauldron Early Script by Rosemary Anne Sisson (Walt | Lot #19097 | Heritage Auctions (ha.com)

If you look at the script's character list you will notice that a lot more characters from Lloyd Alexander's books that are absent in the film. 

Prince Gwydion, 

Queen Achren, 

a young gwythaint, 

bees and bears. (I don't remember any bears in the books.)

  

 (I'm not sure if Mel Shaw did any art with these extra characters. With the exception of the jovial King Smoit. [not in the script?]

                                             (Image source: Tumblr user: hellyeahprydain and  bookshop-belle.livejournal.com)

Her other work for animation that I know of, the script for Thames television and Cosgrove-Hall's stop motion adaptation of Kenneth Grahame's The Wind in the Willows (1983) [aired on ITV in 1983 and shown on The Disney Channel in 1986]

                                                            (Image source: waltsvault)