Leendart
If you don't mind investing £6.95 for a Pay as You Go on
findmypast.co.uk you will be able to download there service records which
MAY provide clues to their deaths
Both appear to be commissioned from enlisted to Officers, so there are both enlisted men and Officer Files, though Officer Files may provide the detail you require
http://search.findmypast.co.uk/resul...me=sullivan%20
Sullivan Frank Harrington — — 1912-20 British Royal Air Force, Officers' Service Records 1912-1920 —
http://search.findmypast.co.uk/resul...tname=sullivan
Frank Harrington Sullivan 1898 — 1917 152777 Misc Aviator Cadet (Student)
http://search.findmypast.co.uk/resul...ame=westall%20
Westall Arthur 1889 — 1912-20 British Royal Air Force, Officers' Service Records 1912-1920 —
Westall Arthur 1900 — 1912-20 British Royal Air Force, Officers' Service Records 1912-1920 —
Results for British Royal Air Force, Airmen's Service Records 1912-1939
Arthur Westall 1900 Middlesex 1918 149706 Engineer
Also CWGC now has Scanned Grave Registration Documents
It mentioned for Harrington that he died while on postal duties and he was from USA
http://www.cwgc.org/find-war-dead/ca...K%20HARRINGTON
Westall has 'Killed in Action' ?
http://www.cwgc.org/find-war-dead/ca...TALL,%20ARTHUR
Paul