As an Eilean

Although this film is in a fictional location, there are few clues as to where it might be. It is clearly a Protestant island, which would exclude the southern Outer Hebrides. The locals also play football (soccer) rather than shinty so that excludes some of the Inner Hebrides and the Firth of Clyde area. It is presumably supposed to be somewhere in the northern Outer Hebrides, and this would match up with the fact it is based on two stories by Iain Crichton Smith (Iain Mac a' Ghobhainn) who came from the Isle of Lewis.

On the other hand, the filming locations are on the Highland mainland, which means that some of the areas are more wooded than most of the Outer Hebrides. The actors speak Gaelic with a variety of different local accents, but they are predominantly from the northern Outer Hebrides.