Murder in the Mews (Hercule Poirot 18)

How did a woman holding a pistol in her right hand manage to shoot herself in the left temple? What was the link between a ghost sighting and the disappearance of top secret military plans? How did the bullet that killed Sir Gervase shatter a mirror in another part of the room? And should the beautiful Valentine Chantry flee for her life from the holiday island of Rhodes?