Leonard was born in 1923 in London to Austrian born Raphael and Annie Tania Shaiman. Leonard had five older siblings, Leah, Lazarus, Isidore, Celia and Helen. In 1939, the family lived at 2 Arundel Gardens, Kensington where their father Raphael worked as a cigarette maker.

Leonard was the wireless operator/air gunner on Halifax LV916 which departed RAF Breighton on a training exercise. After takeoff the aircraft entered a shallow dive and crashed just south of the village of Sutton upon Derwent. 

Pilot, F/Sgt Charles Cliffe Owen Hood, 1339243, aged 22.
F/E, Sgt Harry Bain Allan, 1821830, aged 18.
Nav, F/Sgt John Watt, 659103, aged 24.
A/B, F/O Horace Raymond Goddard, 152303, aged 29.
Sgt Leonard Shaiman
A/G, Sgt Harry Stanley Nelson Steel, 1457502, aged 20.
A/G, Sgt Bernard Frederick Sheerin, 1587508. Seriously injured.