Like some Johns here in Ireland he is also known as Jack.
CATON, JACK
Initials: J
Nationality: United Kingdom
Rank: Sub-Lieutenant
Regiment/Service: Royal Naval Volunteer Reserve
Unit Text: Anson Bn. R.N. Div.
Age: 25
Date of Death: 27/03/1918
Additional information: Only son of John and Eliza Caton, of Abbeyview, Muckamore, Co. Antrim.
Casualty Type: Commonwealth War Dead
Grave/Memorial Reference: I. A. 8.
Cemetery: MESNIL COMMUNAL CEMETERY EXTENSION
He is on the CWGC site and in Irelands Memorial Records on page 28.
Naval records are very good and you have more chance of getting his records than if he was in the army.
lookup the PRO in Kew.
Regards.
Tom.