(at around 31 mins) The prominent painting in the apartment of Eve (Margaret Leighton) of Rave (Laurence Harvey) as a polo player was clearly altered from a copy of one of an American "old money" socialite and sportsman, Winston Guest, a top polo player in his day.
Several of the main cast lived up to the "dying young" part of the title. Laurence Harvey and Margaret Leighton were married in 1957 and divorced in 1961. She was made a CBE, won two Tony Awards, and died in 1976 at age 53. Harvey died in 1973 at age 45. Those of the remaining cast who also met a relatively early demise were Stanley Baker in 1976 at age 48, Susan Shaw in 1978 at age 49, Gloria Grahame in 1981 at 57, and James Kenney in 1987 at 56. As of late summer 2021, only Dame Joan Collins is still alive at age 88. Robert Morley was one cast member to buck the trend, passing in 1992 at age 84.
The gang's car, first seen at the beginning of the film, is a 1951 Jaguar Mark VII.
Hairy-chested Stanley Baker was forced to submit to a full body waxing before appearing in the boxing sequences.
Joe is depicted as flying to the UK on a Pan American World Airways Boeing 377 Stratocruiser. Pan Am flew half of the 56 planes built, from being the launch customer in 1949 until they retired the last one in 1961. It was the first "double deck" airliner. The one seen at the end of the film, registration N1036V, named "Clipper Washington", also can be seen in Ein Stück vom Himmel (1957) and Bedevilled (1955). The one seen taxiing in the rain at the airport with registration N1029V was built in 1949 and named "Clipper Golden Eagle". It was sold by Pan Am in 1966 and was flying with a charter airline out of Miami, Florida until its registration was canceled in 2012.