"I can remember my wife saying - " begins Adam before stopping himself - a rare reference to his being a widower (his US wife was killed in the Blitz), hence Evelyn and Ham's reactions.
Professor Marks dates the skeleton's murder to [Thursday] 12th September 1940, which accurately places it during the Blitz of WW11. From Saturday 7th September onward London was besieged by intensive Nazi Luftwaffe bombing raids for 56 of the following 57 days and nights.