From "A Dictionary For Our Times"

Addendum to the definition for slute :

"The Chieftains are easier to finger as the bottom hole is designed at a comfortable stretch. Many leading players use the Chieftains on stage." - "Hobgoblin Music" catalogue

In fairness to Hobgoblin, this was from the section on tin whistles. The tin whistle used, of course, to be known as a flageolet. That can't be explained by coincidence alone.