Audio problem: The Prime Minister walks to his car, and says "I'd like to go to Wandsworth, the dodgy end." However it's clear his lips don't correctly say "..the dodgy end." (01:38:30)
Audio problem: When David the Prime Minister is trying to get Natalie's Octopus Brother out of the limo, Natalie laughs but we don't hear it. (01:47:29)
Audio problem: During the Christmas concert at the end, Sam's drumming doesn't match the music in some shots. (01:52:10)
Audio problem: During the wedding scene with the choir reveal, various people enter with musical instruments. When the saxophones are playing that they sound like trumpets.
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.