Revealing mistake: S9 E1 "Bully for Ben": When Ben hits the punch bag sideways, it's easy to tell that someone is controlling the punch bag as it never slows down.
Revealing mistake: S9 E1 "Bully for Ben": Ben gets a bullworker out of the box. However, the box is open at both ends and one half of the bullworker is under a sheet. But it is depicted that Ben got it out of the box brand new.
Continuity mistake: S9 E1 'Bully for Ben': When Ben is injured, the sweat stains on his shirt keep changing depending on the shot.
Revealing mistake: S9 E1 'Bully for Ben': When Ben gets hit with the punch bag, you can see him bend down and wait for someone to control the punchbag to hit him.
Answer: Easy. He could have got the guitar at any point in his life. As for keeping it in the attic? You're not going to throw out a £1000 guitar any time soon.
Ssiscool ★