Not renewed due to the death of the main writer (cancer); high cost of production, £1 million per episode; and controversy over historical accuracy (IMO embarrassment in Channel Islands and UK over, respectively, the behavior of islanders during occupation, eg. collaboration, profiteering and fraternization, and the abandonment of the islands by Churchill's government in 1940).
Inconvenient, isn't it, war?
Constable Jonas's WW1 medal ribbons were worn the wrong way around in every episode. The Bailiff, who had the same medals, was seen wearing them the right way around in episode 2.