At the end of the episode, when war is announced, news are met with concerned faces and somber looks by everyone present. Actually, in many places the news were received with cheers, a complete contrast with the serious scene depicted in this episode. By the time the First World War broke out it was the overwhelming feeling among the British high nobility that war would be short and glorious. In fact, there was a generally consent that war was rather "good" for countries, and pacifism was frowned upon, seen as unpatriotic. While Tom, Matthew and many of the servants would possibly have been concerned, people like Lord Grantham would have been ecstatic, or at least some of their guests would be.
When the dowager tells Cora her mother might be coming to visit because Cora is pregnant, Cora says 'Oh god'. This never would have happened in 1914. It would have been considered taking gods name in vain, the same as saying a cuss word. A Lady, a Countess, would never have uttered such a thing, even in private. Daisy, in a later year, says 'God help me', and is warned not to take gods name in vain. Cora became fond of saying 'oh golly' as time went on, which was a very appropriate substitute for 'oh god'.
A modern television aerial is visible on the top right of the cottage.
Mrs. Patmore had cataract surgery. During that time period, intra-ocular lenses were not yet invented and anyone having cataract surgery would need very thick eyeglasses to compensate for the change in prescription due to no longer having their natural eye lens. Without such eyeglass correction, patients would be so blurred they would be barely able to function. Mrs. Patmore is repeatedly shown doing household tasks with no eyeglasses, and at times, she is wearing a very low powered reading glass which would be completely inadequate for near point tasks.