After reading a bit about British Duofolds, this might be one of the pre 1946 NS (New Style) model.
The nib imprint is "Parker Duofold / 14K/ Pen/ N". The N seems to stand for Newhaven - so the nib is British.
It is also a streamlined Duofold and this can also confirm that it is a British Duofold, as only streamlined ones were produced in the UK.
It seems that the barrel imprint was buffed and this caused my wandering whether this it is a legit Parker Duofold.