I actually bought their Christmas single (yes, I really did!) back in 1979, which conatined re-recordings of "Another Brick In The Wall" ("Hey, Santa! Leave that booze alone!"), Day Trip To Bangor ("Didn't we have a lovely time at the office Christmas party; we finished our work and all went berserk" etc), and the real highlight, a new version of the song originally known as "The Sparrow", which went like this:
"I'm only a poor little fairy,
Stuck on the top of the tree,
They switched on the lights,
and bang went my tights,
And my legs fell off, one two three"....