John is listed as being killed in action on 24 July 1916 during the Battle of the Somme. The brief war diary entry for that and a newspaper obituary are transcribed below.
Newspaper Obituary
Stratford on Avon Herald - August 4th 1916
SECOND-LIEUTENANT J.E.F.T. BENNETT
Mr. John Bennett of Cubbington has received news that hios son, Second-Lieutenant J.E.F.T. Bennett has been killed by a shell while leading his men into action. Only last week he earned a promotion for his work as Sergeant of the machine gun section of the Royal Warwicks. Before the war Lieutenant Bennett was a teacher in the Steward Street Council School, having been trained at Saltley College in the years 1908-1910. He was nephew of Mrs. Rouse of West Street, Stratford-on-Avon. END