William Henry son of Joseph Henry and Mary Ann, 1861 census has Joseph Henry in Royal navy ,ports and ships abroad, as blacksmiths crew. This would tie up with William being born Plymouth.
1881 shows him and Mary, (M.A.on census) living Kenton, Exeter, he is working as a laundry servant in brackets it says W & B , so may be the name of a laundry firm, M>A> listed as a laundress, no children at home.
Try looking for his sister Martha, 10 on 1871 census to see where they were in 1861, she was born in Heavitree (Exeter)