I know you posted this a long time ago, but i am currently researching my father's maternal side (ogilby). From her birth certificate i can see her mother was a matilda mchaffey (mehaffy, mchaffy) and her father was a samuel ogilby. I am still waiting for reasearch to come through but i am under the belief that this family is my grandmother's family. She was one of 10-13 children and she was one of the youngest, born 1928 in strabane. I know a lot of her siblings were from strabane, but there is not an ogilby in sight living in strabane in 1911. The only samuel ogilby and matilda mchaffey i can find is these two living in donegal, which is only up the road from strabane in county tyrone.
I will let you know if i find out anymore, but would love any info you may have regarding rebecca's family?