Catweazle

The full rhyme/riddle goes as follows: Twelve are they, the circle round, if power you seek, they must be found. Look for where the thirteenth lies, mount aloft, the one who flies. The hours are they that circle round, thirteen you have surely found, the one who flies is father time. The spell's undone, the treasure's thine.

The Philosopher's Stone is also the title of the first Harry Potter novel, except in the US where it is called The Sorcerer's Stone.

The book written by the Habbleman's is called Toads for the Layman.

Jack Victor's company is called VIRGO: Victor Investments Rehousing Group Organisation

The phone number of Hexwood farm is Westbourne 5839.

The crystal ball shown in Castle Saburac at the start of the episode is the crystal ball stolen from Madam Rosa in episode 5.

First time Catweazle gets to eat a banana, after told how to eat one. He becomes obsessed with bananas and they become a bargaining tool for Carrot in future episodes.

Catweazle is running away from Sam carrying a kettle. He runs through the woods and has nothing in his hands. When Carrot finds the army water tower, the kettle is outside, apparently dropped by Catweazle after running through the woods.