The factory where I work used to be owned by Fisher Humphries who made threshing machines like this http://www.fieldmarshalltractors.com/#/thrashing-machine-restoration/4531453830
Big old thing driven by a steam engine, that was also made at the works at one time, and latterly tractors. As the jack was made in Brum it would be no surprise if it was suplied with one of these.