Corrected entry: At the Christmas party scene, Suzie comes in and Will decides to leave, and then an argument ensues about whether he will leave or not. At one point, Fiona says "I've told Will to go" - except she hasn't said any such thing. It was Will who decided to leave.
Corrected entry: Much is made of the fact that the story is set in the run-up to Christmas. However, this movie was filmed in the height of summer. For example, Marcus turns up at Will's flat "after school" and is shown in bright sunlight with a short, noon-day shadow. School's out at about 4.30pm in the UK, by which time it is nearly dark in November/December in London. Also, in every street scene, the London office workers are swanning around in shirt-sleeves. Rather unlikely for a London winter.
Corrected entry: When Marcus throws the bread at the duck, you can tell that it is a fake duck.
Corrected entry: When they leave to go to the park, Marcus has on the striped jacket. When they get to the park, he has on that blue one with the rainbow and clouds. When they get back home, he's wearing the striped one again. (00:17:00 - 00:23:00)
Corrected entry: At the end of the film Will shows up unexpectedly and interrupts Fiona's SPAT meeting at about the time Marcus's school concert starts. Fiona knew about the concert and that Marcus was going to sing for her so then why wasn't she at the concert on time? Instead she was still at the SPAT meeting. Will showed up at the SPAT meeting unexpectedly but ended up speeding to the concert with Fiona just in time for Marcus's song. How would have Fiona gotten there on time if Will didn't show up at the SPAT meeting?