I went over to Anna's place yesterday to give Sunny her jumper. After we cruelly forced her to stand up from her bed where she was comfortably lying we put it on her and it was too small around the rib cage.
Anna spent the rest of the evening making fun of Sunny for being chubby, which was kinder of her than making fun of the knitter for getting it wrong. Now I'm off work out how to extend the underbelly band. Poor Sunny, bursting out of her jumper!