In the first episode, The German Woman (2002) it is explained that Sergeant Milner joined the police after being been invalided out of the army because he lost part of his leg while fighting. He has a false leg and for the first few episodes he walks with a noticeable limp. However in later episodes his limp has miraculously disappeared and he is able to sprint when he needs to chase suspects.
Whenever action is in London, there is the occasional street scene in which a double-decker bus passes by; this bus is invariably an AEC Roadmaster, the prototype of which didn't see the light of day until 1954, and saw service in 1957/58.
While it is correct to state that the rank of Chief Superintendent was not created until 1949 it was used before this in special circumstances. An officer junior to the assistant chief constable but with a large division or divisions under his control for example. So it is quite feasible that Folye, with such a large section of the south coast under his command was given the superior rank.
In virtually every house or manor that Foyle visits, the bookshelves are empty.
There are multiple instances, in almost every episode, of failures to observe the strict blackout regulations of the period. This is especially noticeable when front doors are opened during the hours of darkness with the house lights being visible from outside.
In several of the later episodes American flags are briefly shown in the background that have 50 stars.
Foyle is a Chief Superintendent. But the series is set during the Second World War and the rank was not introduced until 1949.
Sgt Millner is unable to walk in a way constant with his wound. In the first episode as a soldier in hospital after losing part of his leg. He uses crutches for two episodes and then does not even limp. He swaggers
Not real.