Many writers change the words to their own song either by design, evolution or accident. Apparently Jez Lowe forgot the words of Durham Jail during a performance and had to make new ones up as he went along. He still keeps the line "I hope they let me keep the stripey jumper"!
John Conolly changed the chorus to "Punch and Judy Man" after singing it for 30 odd years simply because he fancied a change! (I like the mark 2 version)
Mr Harvey Andrews himself rewrote "Gift of a brand new day" so it must be alright! (He was also kind enough to allow me to include a verse of my own in Wonderful Day - thanks Harvey, it always goes down well and I always acknowledge that the best three verses are yours)