I believe I do have a timeline of events that you might find enlightening.
In the poem, Jerry tells the audience of the years he spent living with Newt during the war. It was there that Jerry first started writing rhymes, for which Newt would pay him a ha’penny each (on condition that they scan).
Well, since you ask me for a toast…
O Nightingale! O Uncle Newt!
Hilla is surprised that baby Debbie wants to be fed more. Jerry suggests that it’s because she is ready for her pudding. However, Hilla is heard to ask “Well, don’t you want it?”, suggesting that Debbie ultimately doesn’t want her pudding.
The baby is making raspberry noises as Hilla deals with her. Hilla requesting that Debbie saves her “the raspberries of impatience”. This leads to Jerry composing an impromptu, fruit-themed, nonsense song on the piano.
Hilla helps him to find fruit names that correctly scan within the tune.
Jerry is auditioning a satirical song that he has composed about “comfortable men”.
When he finishes, the auditioner points out a major snag regarding the object of his satire – the generation above him served in the war, so can’t be said to have never stood up for anything that mattered.
The auditioner does compliment Jerry’s ability to write lyrics that scan, but still sends him away.