William Purcell married Elizabeth Wordsworth the daughter of Jane Eliza Radcliffe in 1905.
Another daughter Catherine married Thomas Moss in 1890 so this would explain the niece Mary in the 1911 census.
I still cannot find out what happened to Ann Christian Radcliffe daughter of Richard and Ann born in 1837 - she is the only other candidate apart from Jane Eliza to be the mother of John James but she is proving to be elusive.