Cape Fog
Alternate Earth, a group of Scottish witches flee their home in the middle of the night, and with the aid of the Fae steal a ship and sail west. They wreck on the rocky coastline of an island shrouded in fog.
With the aid of the native inhabitants of the island, they find a way to keep it hidden from the rest of the world, safe from the dangers posed by rampant unchecked colonialism.