Audio problem: When Jeremy and James are playing I spy, just as Jeremy says "If you say S, I'm going to kill you!" there is a shot from outside the car and you can see that his lips aren't moving.
Other mistake: When Mattie first gets her kite out, Richard says that they are in the same fjord where Jeremy and James went through the ice. If so, the scenery has changed remarkably in a couple of days. All the blue ice is gone and so are the cliffs, which prevented Jeremy and James driving out. He can't have taken a different route as the fjord is only a mile wide.
Continuity mistake: When James is attempting to outrun The Stig in his van, there is a shot of him along a straight which Jeremy's door is lying in, indicating that he's already passed follow through. The shot then changes to show it from Richard and Jeremy's point of view and James is in the background rounding follow through.
