Leonard Spencer Holmes was one of the eight children of Samuel Lambert Holmes and his wife, Frances nee Spencer. He was born in Ballarat, but enlisted at Geelong on 20 October 1916, following the lead of his elder brother Francis Samuel Holmes. Both young men were bootmakers, following on from their father's trade, single, and, by religion, Methodist. Leonard had served a six year apprenticeship with his father, who had premises at 120 Russell St., Melbourne and lived at 60 Jolimont St., Jolimont.

Len Holmes was almost immediately attached to the Field Artillery Brigade, February 1917 Reinforcements, designated as a Gunner and went into training at Maribynong. Once at the Western front, he was designated as a driver, leading the horses bringing the heavy gunes into place for firing. It must have been a dangerous and physically exhausting job. The unit embarked from Melbourne on 11 May, 1917, on board HMAT Shropshire, disembarking at Plymouth on 19 July, 1917. On 19 July, they marched in to camp at Larkhill. They embarked for France  from Heytesbury on 23 November and on 26 November, marched out to join the 5th Division Artillery at Rouelles (Harfleur). On 2 December, Len Holmes was taken on strength with the 14 Field Artillery Brigade. The Field Artillery Brigades were equipped with specialised weapoons: Siege Artillery, Heavy Howitzers and Medium and Heavy Mortars. In 1916, a fourth battery of four 18 pounder field guns  were added at Division level and in 1917, the batteries were increased from four to six guns each, while the number of Field Artillery Brigades in each division was reduced to two. The 14th FAB had been raised to support the 5th Division in the field, along with the 13th, 15th and 16th and 105th Batteries. Len would have seen action at Passchendaele in November, 1917 and in resisting the German Spring Offensive 21 March-18 July 1918)

Len Holmes became ill with pleurisy on 9 March 1918 and had to be taked to hospital, rejoining the unit three days later. It's not surprising that on 14 March, he was in hospital again and given two weeks leave in England, reporting back on 18 April, 1918. He was then attached to the 13 Field Artillery Battery until the end of the war on 11 November, 1918. He returned to England on 22 May, marching in to Weymouth for embarkation the next day on HMT Friedricharuh and landing in Melbourne on 1 September. 

On his return to civilian life, Len Holmes joined his father and brother as a bootmaker. In 1922, he was living with his father at Jolimont. In 1923, he married Ivy Myrtle Denham, and in 1924, the couple were living at 11 Lorraine St., Moonee Ponds, the same address as his father and only a few streets away from his brother. The couple lived there until 1963, the year Len died, age 69, at Heidelberg, probably the Repatriation Hospital. He was still working as a bootmaker. Ivy died in 1965.