What are the words to 'headmaster's hymn' by Allan Ahlberg?

When a knight won his spurs
in the stories of old,
he was - face the front David Briggs
what have you been told?

With a shield on his arm
and a lance in his - hey!
is that a ball I can see?
put it away.

No charger have I,
and - no talking back there.
You're supposed to be singing,
not combing your hair.

Though back into story land
Giants have - Roy!
This isn't the playground
Stop pushing that boy.

And let me set free with -
Please stop that Paul King,
this is no place for whistlers
we'd rather you sing!

I'm pretty sure those are the words, I just treid to remember them from my head. I apologise if there is copyright on it, if there is, feel free to take it down :)