Above is a thread from 11 years ago which chats about its release on the Universal France CD of Delerue's The Horsemen
There are only 4 cues from "Blind Prophets of Easter Island". Not 'typical' Delerue in my estimation. The first 2 cues + the finale sound as though they could be from an Italian peplum from the early '60s (brassy fanfares, stately timpani, etc.). The 3rd cue sounds most like Delerue, though I don't know what this waltz does for this Easter Island documentary ...