Sorry, my fingers stuttered. It should be the PBS presentation of the Silver Chair from the Chronicles of Narnia.
No worries! I looked up Tom Baker/Puddleglum on YouTube and found the clip where he’s telling the Queen of the Underworld that even if there’s no Narnia, he’s going to live as much like a Narnian as he can. He’s splendid! I’ll look out for the full film. Thanks! had no idea.