Oh dear! I havejust found the following:- In Ontario death records,John Costin d1912 age62 b18 April 1850 IOM father John and mother Ann Duke. Also William Laubman Costin,,b 15 jan1848 IOM d1929 age81, aMedical Doctor. parents John and Ann. Lived in Canada 73 years. (This info has been buried deep in my notes for many years! Sorry!)
So it now appears the help I need is the name of John's, husband of Ann Duke, parents so I can try to fit him in. Our Jane was the d/o William 1812 and Ann Watson.