Hi Peter,
According to the 1881 England Census they had 2 children listed
First one was
Alice Robbins
Born allegedly in 1867
Allegedly born in Greenwich, Kent, England
The Second Child
Percival Henry Robbins
Born: 23 Jun 1871
Baptised: 12 May 1872
England, Select Births and Christenings, 1538-1975
Last found in the 1911 Census
If this is the right person let me know I may have more information.