Hello Paul,
Right now I'm at my office and all of my family tree items are at home. I did however look at the 1871 census that you posted on your web site. I believe the daughters name is Margaret A. (that's my name also). Do you think that Joseph was a sailor or maybe a tailor? Could be a sailor. My ggrandmother Isabella (Casson) Christian, the wife of Joseph, moved with her parents Joseph Casson and Mary (Pearce) Casson from Poole to Whitehaven, Cumberland. This is where she must have met Joseph. Their first child Minnie was born around 1874, however they didn't get married until April of 1876 and their second child William Pearce Christian was born September, 1876. In 1874 that puts Joseph about 19 when the first child was born. Joseph Casson was a Mariner and Mary Pearce's father was also a Mariner. I do have a picture of Joseph Christian, Isabella Christian, Minnie Christian and my grandmother Isabella Esther Cartridge Christian, taken on the IOM at a studio in 1886. If you would like to see it I could send it to you once I get home tonight.
I do have the 1891 census from South street and the 1901 census. By 1901 Mary was not listed and I have been told that she died young. I still have not found her birth or death record. Also listed in 1901 is Joseph the last child.