After cooking dinner and scanning back through the week, I've remembered. Thumbelina by Lucy M George. The story has nothing to do with buttons, but right there on the cover are buttons, enough to send you looking for buttons to do collage with children or sewing buttons onto things.
Since writing about buttons last year, I have also added these two 'button' books to the collection.
Pete the Cat and his Groovy Buttons like all the other Pete the Cat titles has become a favourite with my preschoolers and who wouldn't like to have a pocket full of magic buttons like the witch in Witchety Sticks and the Magic Buttons?