Thanks Fiolar: that is very interesting and helpful. I am fascinated by the origins of Gaelic place names. Tom Barry mentions Ballynacarriga in his book saying that the local Ballynacarriga IRA had organised scouts, supplied food, etc, so I strongly suspected that Granure and Garranure were the same place, but thanks for the confirmation. Re "Caol" - I live in the Cowal Peninsula in Argyll - same derivation!

Careful perusal of the same OS map also shows the "birthplace of Michael Collins" marked. Some of the Boys of Kilmichael participated in his killing.