Frederick Gilbert Stanley Thomas [also known as F. G. Thomas] was born in Camberwell, London, England on 27 July 1898. During World War One he served in the Royal Flying Corps. Following the war, he trained as an architect. On 26 March 1921, he married Winifred Ellen Purcell (1898–1984) and gave as his occupation on the marriage certificate "Architect's Assistant". He was elected a Licentiate of the Royal Institute of British Architects (LRIBA) in 1930 and a Fellow of the Royal Institute of British Architects (FRIBA) in 1934.
A neo-Georgian style house on Oakhurst Avenue, Harpenden, Hertfordshire, designed by Thomas is discussed in Modern Small Country Houses edited by Roger Smithells (London: Country Life, 1936 pp. 106-109)
Thomas's address was given as 42 Rignold Road, Camberwell in 1911 and 1921; 18 Castleford Avenue, Avery Hill, Newham, London in 1933; and 3 Field Court, Gray's Inn, London in 1931 and 1950. He died in Ticehurst, Sussex on 6 December 1984. His address at the time of his death was Terriers, High Road, Chipstead, Surrey
House, Oakhurst Avenue, Harpenden, Hertfordshire (c.1934)