"and I don't think Orkney has anything to compare despite being under Viking control until around 1200 or so." The Hebrides themselves were under Norse control until the middle of the 13thC (ie became part of Scottish Kingdom after Battle of Largs) and of course this artifact was found on the seaboard of the mainland which I presume was itself under contest. Orkney and Shetland were still owned by the Norwegian crown until the 15thC when they were basically sold to Scotland.