Hi again,
Yes this is not an easy one to solve.

H John casey born 1877 islington ?
According to census returns found he was born either 1877 or 1874 Kensington.
The information he supplied for his marriage to Mary Ann Young could have been fabricated as he may not have known who his father was and therefore 'invented' one - it has been known!
There is this 1881 which is a possibility -
Sarah Higson 54
Martha M. Higson 23
Elizabeth Jane Higson 19
Charles Higson 15
Emma J. Higson 10
Kate Brown 70
John Casey lodger 4 b. Kensington, Middlesex
RG11 Piece 49 Folio 123 Page 22
JJ