The Porridge Bird asks if the song came from radio programme Hello Cheeky.
Acording to Wikipedia Feldman recorded one LP, I Feel a Song Going Off (1969), re-released as The Crazy World of Marty Feldman. The songs were written by Dennis King, John Junkin and Bill Solly (a writer for Max Bygraves and The Two Ronnies).[5] It was re-released as a CD in 2007.
Hello Cheeky did not start until 1973, but bearing in mind both Junkin and King were Hello Cheeky performers, it is hardly surprising if the song was performed in the show.
Quack!
GtD.