Continuity mistake: When Jaime and Aurelia are in the lake, after she warns about the eels, Jaime's hairstyle changes between one frame and another.
Continuity mistake: Toward the end of the film when Sam reaches the gate from which Joanna and her mother are departing, he looks down to see them in the boarding line with several people behind them. When he races down to say goodbye, Joanna is last in line.
Answer: It's because of the complications that Sarah was having with her troubled brother. Apart from that, who's to say they don't eventually get together?
Hamster ★
In the follow-up short film (the Red Nose Day special) we learn she eventually gets her happy ending with a man played by Patrick Dempsey.