Mainstay? First I'm hearing of it. I thought it was an onion article at first. It's really hard to tell when British people are serious sometimes. "Conker King"...like, WTH?
“That’s an odd name! I’d a called em fuzzwozzers.”
It certainly is a mainstay. A yearly treat which children love. In Ireland I was taught this song in school: https://m.youtube.com/watch?v=bhebvq0O4GY
(and I still remember all the words)