if you want to trace him back, a good start would be their Marriage Papers, as well as showing his age & his job, it should reveal his Fathers name.
I see that in 1871 she calls herself an 'Officers Wife' .
Given where she's from and where they married, he could well be a Naval Officer?
1891 census might be the key - cant find any of the Family tho

She's 'Head' in 1871, 1881 (West Ham with young son Herbert born Kensington) and 1901 in Hoole, Cheshire.
You could also see his 'occupation' in 1868 by getting Julia's Birth Certificate
Births Mar 1868
Hill Julia Rona I Stoke D 5b 361
===================================
My money's on this lad:
1861 census - Royal Engineer Establishment Brompton Barracks, Gillingham Kent RG9; Piece: 480; Folio: 74; Page: 4
Arthur Hill 19 (c1842) Unmarried - Lieutenant, Royal Engineers. born Devonshire, Stockland.
Births Mar 1842
Hill Arthur Axminster 10 7