1891 census transcript for Alexander Barnett:

Stationed Aldershot with Royal Engineers, Aldershot

Alexander Barnett 38, Head, Born Lambeth London (Lambeth is next to Brixton)

Leah Barnett 32, Wife, Aldershot

Alexander Barnett 12, son, IND (?)

Leah Barnett 9, Daughter, IND (?)

Maud Barnett 7, Daughter, Aldershot

George Barnett 5, Son, Devonport Devon(another military base - like Aldershot still is)

William Barnett 1, Devonport

(Alexander evidently had a large family before meeting Alice.)

"IND" could be "India". Alexander could have been posted there (can't find him in 1881 census; this could be why) before returning to Aldershot, then going to Devonport before returning to Aldershot after birth of William.