Thank you for contacting me - but I don't think I can be much help.
We think that my great grand-father John Kefford, was born in Bedfordshire to Samuel and Sarah in about 1847. He was one of a very large family (12 that we've found) and moved to London in the 1860's.We have no mention of a Sophie.
He married Emily Hull and had 6 children including my grandfather Harry, born in 1876.
Do please keep in touch if you have any information which may help us.