His initials are different in three registers. RIC has Wm A born 1888 in Devon - which will be William Albert Armstrong b1888 in Devon, d 1943 in Sussex. This man was commissioned into South Lancs Regt. I have assumed this to be our man
1888 Aug 25. Born Stoke Damerel, Devon, Son of John Henry Armstrong and Jesse (nee Bradshaw). His father was an Army Warrant Officer, and the children were born in all corners of the Empire.
1911 census at 6 Regimental District, Whittington Barracks, Whittington, Lichfield. He was a soldier in 2nd South Staffs Regt
1915 Mar 24 Landed in France
1917 Nov 28 Commissioned 2nd Lt in S Staffs
1920 Sep 17. Joins ADRIC with service no 585. Posted to L Coy
1921 Mar 12 Posted to C Coy
1921 Apr 2. Posted to P Coy
1921 Apr 6 to 19 Apr on Leave
1921 Apr 28. Permitted to resign.
1939 Living in 17 Links Road , Portslade-by-Sea U.D., Sussex, with Jesse Armstrong (this will be his mother who died in 1950). He is an Army Pensioner
1943 Dec 11. Died Worthing, Sussex.