William Henry, born May 10, 1872 in Dorchester, Dorset (or Porston or Forston, Dorset according to 1881 census).

1901 census:
Name Age in 1901 Birthplace Relationship Civil Parish County/Island
Eve M Selley 8 months West Ham, Essex, England Daughter West Ham Essex
Lizzie M Selley 27 West Ham, Essex, England Wife West Ham Essex
William H Selley 29 Dorchester, Dorset, England Head West Ham Essex "police constable dock boy"
Registration district: West Ham
Sub-registration district: Canning Town

Eve is Eva Marjorie, born Aug. 4, 1900.
William was born in 1902 and James Arthur February 22, 1905

I couldn't find William in the 1891 census but he was in the 21st Hussars for a number of years so may have been away.

I was told that the family went to Canada c1905.

From 1881 census:
Name Relation Marital Status Gender Age Birthplace Occupation Disability
Henry Selley Head M Male 37 Exeter, Devon, England Gardener Domestic Servant
Sarah Selley Wife M Female 39 Blandford, Dorset, England Wife Of Gardener
Sarah Selley Daur U Female 12 Porston, Dorset, England Scholar
William Selley Son Male 10 Porston, Dorset, England Scholar
Maria Selley Daur Female 8 Dorchester, Dorset, England Scholar
Charles Selley Son Male 4 Exeter, Devon, England
Arthur Selley Son Male 1 Weymouth, Dorset, England
Dwelling Agra Place
Census Place Dorchester St Peter, Dorset, England

In 1901, Henry is living with daughter Maria
ivil parish: Dorchester St Peter
Ecclesiatical parish: Dorchester Holy Trinity and Frome Whitfield St Nicholas
Town: Dorchester

In 1891
Selley, Henry abt 1843 st thomas oxeter, Devon or Devonshire Head Westerham Kent
Selley, Sarah abt 1842 west allington bridport, Dorset Wife Westerham Kent
Selley, Arthur abt 1880 st johns weymouth, Dorset Son Westerham Kent
Selley, Charles Exeter, Devon or Devonshire Son Westerham Kent