The last scene where the bells are ringing takes place on Christmas Day. At that point in the war, bells had been halted from ringing, with three exceptions: once by accident, on November 15, 1942 to celebrate victory at El Alamein and the tide of the war turning, and then on Christmas Day 1942. Restrictions would be completely removed at the end of May 1943, when fears of a German invasion had receded.
The title of the episode is derived from the Episcopal (Anglican) Advent hymn: "In the Bleak Mid-Winter". Very appropriate choice for the time line. (Advent is the four weeks in Late November and on into December that leads up to Christmas.)
Jane Milner refers to the Matrimonial Causes Act of 1937. In this act one of the grounds for divorce is that of abandonment for a period of at least three years. If she had stayed away for three years she would have no legal grounds to fight a divorce. As she had been away for less than three years, Paul would have to fight her in court, proving that her attempt to return was not due to reconciliation but because she wanted to take advantage of him.