Lady Di, I did my mothers family tree a number of years ago. During the seemingly impenetrable details pertaining to the research, I discovered many, many spelling errors, writing errors, print errors, mainly by those recordists that should have known better, but hindsight is a wonderful thing.
Blinkered as I no doubt was by the Seward name during research some years back now, I found this other Seward somewhere in the official records. Assuming Cravan was a misspelling of Garvan, mere mention of a Elizabeth Alice on the birth certificate, plus, like you, not being conversant with London at all, I assumed the link was within my family........ alas I was again in error. I currently flagellate myself myself on the hour with a slipper made of steel...... to assume in family history is the road to perdition....
I do hope I have not upset, or caused unnecessary time wasting on my behalf in this confusing Seward saga to anyone. I like to think that out of it all, I now have some degree of accuracy and confirmation in my familial history. For that, I thank each and every one of the contributors to my quest, thank you.