Many of the former sugar estates or cotton plantations on the island were named after their (former) owners, and many of the villages are named in turn after the estate or plantation where they are located. So a centuries-dead owner called Brade is perpetuated in the village of Brades; the village in which I stayed on my first visit to the island, Tuitt’s, keeps alive the name of the Tuitt who once owned the nearby estate.
Etymologically, then, these are possessives, and accordingly they are sometimes (though inconsistently) written with an apostrophe. See, on the first map, Brades but Trant’s and Tuitt’s.
There is the usual problem in cases where the former estate owner’s name ends in a sibilant. Near Bethel, just to the south of the dotted red line marking the limits of the exclusion zone (access forbidden because of continuing danger from the volcano), you will see a village labelled Harris. However this village, sadly destroyed in the volcanic disaster of 1997, is/was known as ˈhærɪsɪz (well, ˈharɪsɪz). I feel inclined, therefore, to spell it Harris’s. The local school teachers, anxious to be correct, tended to write Harris’. But as you can see, the map makers wrote Harris, apostrophe-free, and this is/was the predominant spelling.
Here’s another map. Again, we have Harris, but also Harris’ Lookout. More interestingly, this map shows another village, labelled Farm. But everyone calls/called it faːmz.
A recent government report reported on plans for geothermal drilling “between Weekes village and Garibaldi Hill”. I can tell you that the name of the village is pronounced ˈwiːksɪz.
There’s another village, one still unaffected by the volcano, called frɪts (actually, Upper and Lower). How is it spelt? Either Friths or simply Frith. (Bear in mind that in Caribbean English you tend to get t for standard θ, so frɪθs simplifies to frɪts.)