Lady Chitterly is the only character to ever call Hogan by his first name only, Robert.
Regarding pre-war association with Lady Chitterly, Hogan said he was not part of the 'Cliveden Set.' Nancy Astor, Viscountess Astor had a country home, Cliveden Manor where she entertained select members of the aristocratic upper upper class. This Cliveden Set was reputedly in favor of the Nazi agenda and not quite covertly supported it.
This is the second time where an Allied soldier impersonates an Axis enemy. The first being The Prince from the Phone Company (1966).