When on the roof of the chapel at Torrecastro, Cooper indicates a Frenchmen (who had shot at him) with the words "Left - three o'clock". This is a phrase which would only be used by someone familiar with a clock face (which Cooper may not be) and three o'clock indicates 90 degrees to the right (not left). He then actually aims slightly towards the right of the square (more like one o'clock).
At the end as Sharpe and Hogan watch Teressa leave, the union flag on the building is upside down (as determined by the wide white areas of the St. Andrew's Cross relative to the half width diagonals of the red St. Patrick's Cross). When Sharpe descends the steps and stands in the road, it's up the right way.
In the abandoned cottage, Harper bends and reacts to Sharpe's kick to his groin a split second before Sharpe's foot actually connects, even though Harper's face is turned away looking behind him.