Are you sure it's Enya? The reason I ask is that a similar question has cropped up in the Adverts section about the Cheltenham & Gloucester ad - young boy swimming around underwater and finding a pearl, pinching it from under the noses of people in full diving suits. The music on that ad (which sounds a little Enya-esque) is from Adiemus, composed by Karl Jenkins.
Or is it an actual Enya video (in which case either she's ripped off the ad or vice versa)?