I am also tracing Cleasbys in London. Looking for the parents of Joseph James Cleasby b. c1840 London, Middx., d.1893 Whitechapel. He is shown as a Bookbinder in 1881 census, married to Eliza b. c1839 (nee Sutcliffe). Children: Martha Eliza b. c1865, William b. c1868, Alfred George b. c1872, Leah Mary b. c1874, Richard George b. c1875, Florence b. c1879. Address 36 Bartholomew Close, London, Middx. EC1A7.
I also noticed on the 1881 census another Cleasby family headed by Frederick J Cleasby who is also a Bookbinder aged 39, b. c1842 London. Are they brothers? Seem a co-insidence as the address at 20 Bridgewater Square, London, EC2Y8, is close by to Joseph James Cleasby's address. Any information welcome.