Morag, I am researching the Quilliam side of my family as my mother was married to George Ernest Quilliam from 1934 to 1940 when he was killed in a bombing raid on Liverpool. She later married my father. Ernest Quilliam was the youngest son of Samuel and Margaret Quilliam (nee Costain) and I believe this to be the sister of your relation John Costain. I have a handwritten 'Family Register' page giving Margaret's birthplace as Colby IOM and dob as 13/5/1858. FYI really I'm afraid as I have not yet researched earlier family members.