I know some hearty folk, Whose party jokes pretending to hunt with the Quorn
Solution 1:
The Quorn is a famous English fox hunt.
Not only is it one of the most famous hunts, it rhymes with Horn so fits the song.
It is based in the Leicestershire village of Quorn.
Foxhunting is no longer legal in the form that it was at the time of writing the song, so the name is not so familiar nowadays. However, most British people in the 1960s knew of the Quorn, and many still do.
Don't forget that Flanders & Swann wrote this long before the meat substitute was invented.