I listened to Discovery yester-day, and even before it got to this part in "The Diary of Horace Wimp," I was pretty sure that the tubular bell part (after "And she did" in the Sunday verse) was just a scale. I figured out that it's a Bb major scale, although the last note is the same pitch as the first.
This is an extremely small part of the song, but at least now I can be pretty sure that the rest of the song is in Bb major too.