I just checked the Project Gutenberg on-line text for 'The Girl on the
Boat' and found that P.G. Wodehouse himself knew about the things.  It's
in chapter 9, at least.  Glad to see it made its way into the film.

Here's some text that shows P.G. must have undergone the delight of
hearing one that was ill maintained:

  http://www.gutenberg.org/dirs/2/0/7/1/20717/20717.txt
  The Girl on the Boat, by P. G. Wodehouse

  "The late Mr. Hignett had it put in.  He was very fond of music.
It's a thing you turn on by pressing a button in the wall," continued
Sir Mallaby.  "How you stop it, I don't know.  When I was down there
last it never seemed to stop.  You mustn't miss the orchestrion!"

  "I certainly shall," said Mr. Bennett decidedly.  "Music of that
description happens to be the one thing which jars unendurably on my
nerves.  My nervous system is thoroughly out of tune."

  "So is the orchestrion," said Sir Mallaby.  "I remember once when
I was down there...."

Peter Neilson