Information from the censuses
In 1911 William Henry Callen, then 45, born in Eastleigh, Hampshire, was living with his wife Ada Elizabeth, 47, born in Woolwich, at 100 Dorset Road, where the family occupied 4 rooms. Callen was a railway porter. His children, all born in South Lambeth, were Jessie Marion, 17, no occupation listed; William George, then 15, who was to die in 1920, presumably of wounds sustained in the war; and Florence Elizabeth, 13. The 1901 includes a third daughter, Margaret, born in 1900. At that time the family was living at 12 Walberswick Street.
The 1911 census shows that William Henry and Ada Elizabeth had had 5 children, 3 of them surviving to 1911.