The opening sets the scene in Scotland but the pipe band is playing a famous Irish tune, Brian Boru's March.
When the "ghost" is preparing to ride off to war, he is wearing plaid pants rather than a kilt. Later, he arrives at the battle site and is wearing a kilt. One wonders if the issue has to do with him mounting the horse and the enactment of the Hays Code aka code of decency in the motion picture industry which went into effect c 1934.
Having come to dinner at the castle in a tulle evening gown, Peggy decides on the spur of the moment to spend the night. Yet next morning she comes down in a daytime outfit, which she obviously would not have had with her.