Bert and many others have done this - in fact many have done so.

How many people sing the first part of Hal-an-Tow as

When man was first created
his works have been debated
and we have celebrated
the coming of the spring/May.

Pure Mike Waterson, who didn't like the way the song started so started it with a new verse.

The point is not to make up, add, delete alter and generally transmogrify words, verses songs etc. by any definition that is the folk process. The trick is not to copyright your version. Otherwise the process stops.

And I don't own a telly.