The above link is to Frank and family in 1891. His parents are Thomas and Sarah .
Thomas Eastwood, a widower, married Sarah Stancell nee Jackson, a widow, in Sheffield 19 September 1873.
Thomas had previoulsly married Harriet Wedge in 1867 and had 2 children, Florence born 1871 and William born 1871. Harriet died in 1872.
Sarah had married Thomas Stancell in 1867 in Lincolnshire and they also had tow children, William in 1868 and John Henry in 1870, before Thomas died in 1871.
Hoprfully this will now help you to work backwards usin the Census records and the GRO indexes and if you have access to findmypast then images of the marriages are available at a price.