Yes, he did write a song about it - I'll dig all the words out later. Meanwhile, this is the bit I remember:

I don't look a bit like Santa Claus,
The verdict is official.
If the beard on me is all you see
Then your look's quite superficial.
There's Karl Marx, and Henry Parkes,
With whom I can be compared,
But it's plain to see that you don't see me
If you just see the big white beard.