"As for non-Scandinavian roots, you wouldn't find many Anglo-Saxons in the Highlands and Islands till fairly recently, and their place-names are usually recognisably English rather than Anglo-Saxon."

Quite so common sense suggest it is Scandinavian rather than Anglo-Saxon. The Hebrides were owned by the King of Norway and didn't come back within the Scottish kingdom until about the 13thC or so and of course the Northern Isles were Norse for another couple of hundred years. The Scottish isles are littered with names of Norse origin.