Actually the first Grizabella was T.S. Eliot. He didn't include the Grizabella poem in "Old Possum's Book..." because he thought it too sad for children. But his widow gave ALW the unfinished Grizabella poem.
Also, long before Dame Judi had it, there were some performances of the role as ALW was fine tuning the music and trying to interest producers in the show.
If anyone ever tells you that you put too much Parmesan cheese on your pasta, stop talking to them. You don't need that kind of negativity in your life.