Leonard Bostock, medical practitioner, was the son of Benjamin Sylvester Bostock and his wife Ellen. He studied medicine at Owen's College (which later became Victoria College), Manchester, and at St Thomas' Hospital, London, and qualified in 1893 as a licentiate of the Royal College of Physicians of Edinburgh, a licentiate of the Royal College of Surgeons of Edinburgh, and a licentiate of the Faculty of Physicians and Surgeons of Glasgow. He was licensed to practice in the South African Republic (Transvaal) in 1899. During the Anglo-Boer War (1899-1902) he served as a major in the South African Medical Corps and was a civil surgeon in the South African Field Force. In 1903 he entered the service of the Witwatersrand Native Labour Association and remained with that association until 1940. Shortly after the Anglo-Boer War he was posted to Komatiepoort, Mpumalanga, where he was already serving as district surgeon in 1907. At some time before the end of 1914 he moved to Porto Amelia (now Pemba), on the north coast of Mozambique, but may have returned to Komatiepoort at some time. Later he was medical officer in the Witwatersrand Native Labour Association's Kazangula Camp in present Zambia.
In 1905 Bostock published an article on "Malarial fever, its causes and prevention, with notes on the methods taken for its diminishment or eradication in Komatipoort" in the Lourenco Marques Guardian. The article was published also as a pamphlet in Lourenco Marques (now Maputo, Mozambique) in 1905 (16p). A second edition of the pamphlet was issued in 1912. In 1908 he obtained the Diploma in Tropical Medicine at the University of Cambridge. A few years later he published Health and sickness in the tropics; a guide for travellers and residents in remote districts (London, 1913, 94p).
Bostock also held the posts of British Vice-Consul, Porto Amelia Agent, medical officer for Portuguese Nyasaland, and railway medical officer in the Transvaal government service. He was first married to Kate (or Kitty) Wood and was survived by his second wife, Sheilagh Maureen Bostock. He had two children from his first marriage.