Searching for "Ill Fares The Land" 1983, I came across this review:
However then there was this expose - it wasn't filmed on St.Kilda at all:
Michael Powell, who some modern critics would argue was the best film director Britain ever produced [only some? :)], was fascinated by the St Kilda story from the time he heard about it in 1931. At that time he had scarcely embarked on his career but with admirable determination he was able, in 1936, to realise his ambition to make a film about the island. The Edge of the World (1937) could not, unfortunately, be made on the island itself.
The other dramatised account of the last days of St Kilda had also to be made at some distance from the island group. Bill Bryden's Ill Fares the Land (1983) was shot on the mainland at Applecross and was less geographically faithful than Powell's version but more accurate in other ways.