The choir was the real choir from the local Methodist chapel. When he heard them singing, director Michael Powell said they were too good and he wanted them to sound "more ragged, like a choir of country folk" only to be told "But we ARE country folk, Mr. Powell."
The commercial failure of that film was what led to the dissolution of the partnership between Alexander Korda and David O. Selznick.
The brass band that plays in the film was the Condover Brass Band, with actor Peter Dunlop in the part of the cornet player.
The bird twittering sound effect is a looped recording that was used by the band Pink Floyd in the track entitled "Grantchester Meadows" on the album "Umma Gumma" The lyrics refer to a fox gone to ground.