I don't have access to the 1939 register, what occupation does it have for Kathleen? There is a report in June 1939 of a Kathleen MILLINGTON killed in a car accident. She was a nurse, of Hawarden (about 7 miles from Chester). though I can't see a death registration. (The trial was in June 1939, so the accident may have been earlier, so it may not be "this" Kathleen.)
Monday, June 19, 1939
Publication: Gloucester Citizen
Can't see any obits for Ronald or Jessie in papers I have access to.