Manx Genealogy

History of Charnley name

I live in the Toronto area of Ontario Canada. Out of 6 million people there are a literal handful of Charnleys. To my astonishment one of them contacted me out of the blue...his name is Jeffrey Charnley!! And he told me that for 800 years the Isle of Man was known as Charnley Island. Is there even a shred of accuracy to this? My family hail from Lancashire..Blackburn, Bolton, Southport..and trace back to the mid 1800s, but a sister, still in England, says she's traced back 400 years. But no-one has ever said a thing about the Isle of Man. Can anyone help, please. Thanx to the Manx, in advance!