Uther is left-handed but during the fight with the dead knight, the stunt actor who fights in place of Anthony Head is right-handed.
When Arthur is first crowned and stands up, all his hair is behind the crown, but after he turns around, some of his hair is in front of the crown.
After Uther kills the wraith, he takes his helmet off with his left hand in a close shot. He is then seen from a distance with the helmet in the right hand; his left hand empty; his sword on the ground a few metres away. Then in another close shot, he throws the sword to the ground with his left hand.
When Sir Owain accepts the challenge, the black knight says the duel will take place at noon. However, as Arthur and Owain are walking into the arena, the shadows on the ground clearly indicate that it is either early morning or late afternoon.