Hello
I've come across this posting when trying to knock down a brick wall of Mary Connely, born in Sheerness. I haven't been able to establish for definite further back than her, other than her father being a painter called Henry Connely. I have found a likely father in 1861, who is in the household of his son Frederick, and another son, Alfred, is also there. Both Frederick and Alfred are the same age as in your posting, so I'm hoping there's a link here. I can't at the moment prove the connection. Do you think Mary could be Frederick's married sister?
Happy hunting
Caroline