Goofs

Christopher Robin had left school before the war began.

Winnipeg (the namesake of Winnie-the-Pooh) is repeatedly identified as male. The real Winnipeg was a female bear.

When the Guards band are playing, several are wearing modern day medals (Iraq, Afghanistan etc.). The close up of the cymbal player shows the Queen's Golden and Diamond Jubilee Medal which weren't awarded till 2002 and 2012, alongside a LSGC with Queen Elizabeth II on it.

In the scene at the station when Christoper Robin is leaving for the army, there is a map of Southern England on the wall behind them.

During the war, all maps and signs were removed from public places, as these could have aided the enemy.

In the beginning of the movie C.R. Milne's original stuffed animals that inspired Winnie-the-Pooh Piglet Tigger Kanga Roo and Eeyore appear. But in reality C.R. Milne had lost Roo a long time ago at an apple orchard when he was 5 years old.

In the night scene with Christopher and nanny, when they throw sticks into the river, the fragment of the appearance of the sticks from under the bridge is the same as the day one, when Christopher and his father threw the sticks. Only a dimming filter was applied.

One of the players in the costume parade is identified as "Queen Elizabeth the First". At the time, she was the only Queen Elizabeth.

When Christopher Robin visits London Zoo (in 1928), he watches penguins swimming past a viewing dome set into the side of their enclosure, known as Penguin Beach. This wasn't built until 2011. In the director-screenwriter DVD commentary at 0:28:24 director Simon Curtis mentions "And we cut to these shots where it's actually the real London Zoo at Regent's Park. And this window, this circular window is apparently accurate to the interwar years." An underwater, flat, circular window may have predated World War II, even though an underwater, three dimensional, spherical window did not.

In the station there was a poster for British Railways. BR did not exist until 1948. CR would have joined up before war ended in 1945.

When the Guards band is playing for Christopher Robin's birthday, they mark time out of step with the music (the first beat of the bar should be on the left foot). The apparent error probably arose in the editing stage.

Alan and Olive have great difficulty with the chickens escaping as they attempt to transfer them by hand from a small cage to the main coop. This is because what they should have done is place the cage inside the coop and then open it.