The only one I could find in the 1881 Census
Walter Horace Spragg born 1864, Clerkenwell Middlesex, at the time of census he is listed as a Carpenter. That would make him 15 years old in 1879, Drummer boy maybe? Being so young, acting like a child later in life ??
Father Walter born 1835, London
Mother Marion born 1835 Windsor.
5xSiblings, only one sister as mentioned in the article.
One brother being named August, born1856, Bloomsbury.
It's unlikely, but the article states the brother as Augustus.
Also for this to be him his age in the article has to be a mistake, as this man would be 51 in 1915.