Eh - I came back after feeding ponies and saw your thread... pinged my triever lovin' buddies. Now I am goin' to bed :~D
You wonder if the dog was heading for England knowingly, and what means it used to keep a steady course, since its rumline extended over the horizon and he had no compass, sextant or GPS:-D Did he orient himself to the direction of the seas, check the sun's position, or merely rely on his sense of smell?
I'm e-mailing this article to my sister in law who loves dogs and has eight, two of which are labs.