Matthew Chapman born 1844 Sheffield Birth Certificate

So, this is Matthew Chapman's birth certificate (1844).
Matthew is the brother of Joseph Chapman, my great-grandma's (Ruth Howson nee Chapman) father.Just to complicate the Jubb/Chapman saga even further, there is no father recorded on Matthew's birth cert.Like...WHY?Curiously, Matthew Chapman appears to metamorphose into 'Matthew Jubb' as from the 1871 census.Like....WHY?Matthew's mother, Ruth, appears to have given birth to him in Armitage Square, High St Lane, off Duke Street, Sheffield Park, a place I must have walked passed a million times! 
I've posted a modern-day picture of what I presume to be Armitage Sq below. 

At the bottom of Duke Street, Park Square roundabout just over the bottom of that road.