Birth registration on GRO index has the H as Hopkins not Henry

WILLIAM JOHN HOPKINS BARBER no mothers maiden name given
1876 M Quarter in CANTERBURY Volume 02A Page 783
There are online Army records for a William John Barber bn Canterbury but the age on those leads to the 1872 birth. He was in the 3rd East Kent regt.
Who were the parents of your William as I can only see the William born to William Barber & Jane Amos in 1881