Thanks for the very helpful thoughts. It is unlikely that there is a coincidence as both were in the same parish/ward of London (St Giles in the Fields) and the child's first names, Edmund George Cooper, are not particularly common - had they been Albert or the like then it could be different. The adoption is a possibility - although as far as I can trace the natural mother died in 1853. I had assumed that until I found the baptism record that mother's name and status on the birth certificate was as you said fudged. All I can guess is that the woman to whom he was married and he lived apart but for reasons of respectability he prevailed upon her to be at the baptism as the child's mother. But even this is at the boundaries of speculation.