"a past that is glorified as good, stable and, really, a lost utopia."

I think that's a mischaracterization of Foyle's War.  It shows a war-time England of black-market corruption, military cover-ups, upper-class treason, police malfeasance, and (immediately postwar) political dirty tricks.  Hardly a lost utopia.  More like the story of one honest policeman in a dystopia.