Revealing mistake: In Series 2 Episode 4, "Trust Never Sleeps," Ben can be seen urinating from a window and Susan slams the window shut. However you can plainly tell by the way Ben is standing that he is not urinating at all.
Continuity mistake: Susan is on the phone to a neighbor. Susan then shouts, "Ben!" Surely the neighbor would know it's Ben and Susan.
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 ★