Hi there everyone and thanks for the assistance, but am going to close this one as it seems unlikely that anything will be found.
Have had some more information about John. It appears that both he and his wife, still no name, had belonged to a wealthy Catholic family, had become Protestant, and were cut off completely by the family. It was actually John and his wife who died in the famine, not his parents. The two children were taken in by different families. Hugh's sister was adopted by a family named SMITH and they emigrated to the US.
Ian C
