The liner notes from Oak: Welcome to Our Fair (1971) about Thousands or More:

Oak got this one from the singing of the Copper family of Peacehaven, Sussex. The good old folk singer George Townsend, who lived not far from Peacehaven, used to sing a similar version in two-part harmony with his father. It’s a composition by Samuel Arnold, proprietor of the Marylebone Entertainment Gardens and founder of several London glee clubs at the turn of the eighteenth and nineteenth centuries. Thousands or More became popular with country singers towards the middle of last century, when the choral society and part-singing club movement began to affect villages close to the towns.