Tom, you mentioned a Caldwell getting land some 200 years after the battle of Largs. 40 years ago John Caldwell of Paisley (were I was born) told me of the story of a Norseman, Kald, taken at the battle of Largs (1263) who, after serving time labouring on some farm, was freed and settled in or around the village of Caldwell near Neilston. There being artesian wells thereabouts he was know as Kald of the Well. With the anglicanization of names this became Caldwell, similar but unrelated to Coldwell, a common name in England. Caldwell is not that common in England and the largest concentration appears in Lancaster where a significant number of Irish settled. Interestingly there were only 44 Coldwells in 1881 in Scotland most in what was Northumbria. Compare this to the 2513 Caldwells in Lowland Scotland, 217 of whom from Ireland and 2 from the USA! In Nouthumberland itself there were only 4 Caldwells versus 47 Coldwells.
My parents live in Largs by the way.
Best regards.