When the boy and the Snowman take off to go to the North Pole, they appear to fly over the South coast of Britain (as per the piers at which seems to be Brighton) they then when they near the pole spot penguins (which live in the southern hemisphere), however when they land they arrive at a party with Santa who is purported to live in the North Pole. This slipup is doubled when they fly back from the South they pass over the piers again to land back in the garden.

(Other than this, I love watching this film with the kids)