Near the end of that YouTube clip with the "Nonsense Songs/Songs of Fun" grouping,
Martyn Green recites the following tongue-twister.

Betty Botter bought some butter,
But, she said, the butter's bitter;
If I put it in my batter,
It will make my batter bitter
But a bit of better butter
That will make my batter better.

So she bought a bit of butter
Better than her bitter butter,
And she put it in her batter
And the batter was not bitter.
So, 'twas better Betty Botter
Bought a bit of better butter.