The opening shot shows the sun and the moon in the sky. However, the sunny side of the moon is facing away from the sun. This never happens in real life; the sunny side of the moon always faces towards the sun.
Henry Howard says several times that the motto of The Order of the Garter Honi Soit qui mal y pense means evil to him who evil thinks. In reality it means shame on him who thinks evil of it. It was supposedly said by Edward III when a lady dropped her garter and he picked it up and chided the other guest who thought that him doing that meant that he was having an affair with her.