There are an amazing number of "cut & paste" trees for this man that are completely wrong. The marriage in 1915 is on the date in the RIC Register, and his name is Frank Walter Hooper, and his dob is confirmed in 1939 resister & Ric.
1889 Apr 20. Born Barton Regis, Gloucs as Walter Frank Hooper. (date in both RIC & 1939 Register)
1891 census at St George, Gloucs
1901 census
1907 Sep 16. Enlists in RFA as #47984
1911 census. He is an RFA Gunner at Louisberg Barracks, Royal Field Artillery, 134Th Battery, Bordon
1914 Aug 28 Lands in France
1915 Aug 11 Married Elizabeth E Clatworthy in Bristol (date as in RIC Register)
1918 May 5 Discharged from RFA with SWB
1921 Jan 7. Enlisted RIC no 77455 & ADRIC no 315 (841 ). ex-Soldier & Storekeeper
Posted 4 Gds
Posted to R Coy
1921 Oct 25 ro 23 Nov in Stevens Hospital
1922 Apr 1 Gets a Seaman Card. Same address as pension card
1939 Register He is living with wife Ellen E Hooper at 9 Park Av, Bristol. He is a Labourer
1949 Died Bristol as Walter Frank as he had been born