This is certainly the right man - there are no other alternatives. Born as "William Albert Nickolay", he seems to have served in WW1 as "William Frederick Nickolay" , and died as "William A Nicholay(sic)"
1890 Feb 20. Born Hanwell, Middlesex "William Albert Nickolay"
1891census at Strand, London
1901 census at 66, Neal Street, St Giles In The Fields And St George Bloomsbury
1911 census at Lance Corporal 2/East Yorkshire Regt, at Fyzabad, India. 1915 Jul/Sep married in Hull to Ethel Martyn (they had 2 children, one was William Harold Nickolay 1918-2000)
1915 Nov 14. Landed in Balkans
1916 Nov 14. DCM gazetted
1917 Apr 5. Commissioned 2nd Lt
1918 Oct 15 Promoted Lt. E. York.R.—W. F. Nickolay, D.C.M.
1920 Mar 13. E. York. Reg. . Lt W. F. Nickolay, D.C.M., retires, receiving a gratuity.
1921 May 19. Joined ADRIC with service no 1989. Posted to R Coy
1921 Aug 15. Permitted to resign on disciplinary reasons
1939 Mar 8. The undermentioned having attained the age limit of liability to recall cease to belong to the Res. of Offs.: — E. York. R.—Lt. W. F. Nickolay, D.C.M.
1939 Corporal in RAF
1961 May 5. Died Hull