Ernest Clifford Lavender was born in Walsall, Staffordshire, England on 17 February 1890, and was the son of the architect Henry Edward Lavender (1856-1935) with whom he may have received his training. He was in partnership with his father in Walsall until 1932. He then formed a partnership Alfred Richard Twentyman (1903-1979) as Lavender & Twentyman. The practice had an office at Waterloo Chambers, Waterloo Road, Wolverhampton, Staffordshire.
Lavender & Twentyman designed numerous buildings in the Wolverhampton area. These included the Accident and Emergency Department of the Eye Infirmary in Wolverhampton. Houses in Tettenhall, near Wolverhampton designed by Lavender & Twentyman are discussed in Small Houses £500-£2500, edited by H. Myles Wright (1937 pp. 37, 78-79).
Lavender was elected an Associate of the Royal Institute of British Architects (ARIBA) in 1918 and a Fellow of the Royal Institute of British Architects (FRIBA) in 1932. He died on 4 December 1942. At the time of his death his address was given as Chesterton Lodge, near Bridgnorth, Shropshire.