By is there anywhere except the IGI marriage where her surname is given as Corteen, I meant family records (e.g. a bible), or a burial or MI. The parish registers could have been difficult to read. I found in old wills that Costeen and Corteen were almost impossible to tell apart, but Cotteen and Cojeen should have been reasonably clear. - Perhaps one of the vicars entered the wrong surname for her.

Sue