Rilian wears a mask over his face in this film, a device which does not appear in the novel. This was added to the story to keep the audience from immediately recognizing him, as Richard Henders also plays the part in a flashback earlier in the film.
Barbara Kellerman, who plays the Green Lady, previously played the White Witch in The Lion, the Witch, & the Wardrobe (1988). This has led to the popular misconception that the two characters are the same person. In the book, it is merely suggested that the Green Lady is one of the Northern Witches.
Before his death, C.S. Lewis sold the adaptation rights to the entire "Narnia" series. At that time, he absolutely despised television adaptations of his books, believing they were non-realistic, since actors had to wear suits to play non-human characters.
Experiment House satirizes progressive educational institutions such as Summerhill School in England, which were fashionable at the time. CS Lewis also based Jill Pole's experiences of bullying on some of his own. In the book, the head of the school is female.
It is unclear whether the Lady of the Green Kirtle is the same person as the White Witch. She is merely described as "one of the northern witches" (a nod to Lewis and Tolkien's fascination with the Kalevala, the national epic of Finland) However, the actress Barbara Kellerman plays both.
There are some scenes unrelated like the dragon appearing at Ruined City of the Giants. At the end of the miniseries, when they emerge from the Underground Kingdom it is summer, during the day. In the book, they emerge into Narnia during the winter, in the middle of a celebration, at night.