Thanks Brian
I have had problems with others pronouncing Caldwell in our family travels. In Scotland it was ok in Wales it was Cornwall (unsurprisingly), My mother said she did not meet any other Caldwell's in Wales.
In Australia it has been mainly Caudwell but I have often had mail addressed to me as Cladwell. Where we live seems to be easier but our family has been here for a while and I have met other Caldwell's. Perhaps the name is better understood here.
I don't think Caldwell is particularly common any more in Scotland but it seems to be more common in Northern Ireland and the USA.
There is a possibility that out family had been to Ireland and had come back but it would have had to hav been before about 1780.
Look forward to hearing from you if you have success at Largs.
Tom