Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 133,095 pages of information and 210,772 images on early companies, their products and the people who designed and built them.
Makers of fuel economisers, of High Holborn, London
1933 Senior Economisers was established by a group of former employees of Green's Economisers as a rival concern.
1947 The company was listed on the London Stock Exchange as Senior Economisers Ltd. The directors included David Cecil Lycett Green and Francis Dene Lycett Green (presumably from the same company who ran Green's Economisers). The company's products would continue to be made for it by International Combustion Ltd
1959 Acquired Cupodel Ltd
1961 Manufacturers of fuel economisers and accessories. Subsidiaries are engaged in the manufacture of light gauge ducting and fabrications in mild steel, aluminium and stainless steel; specialists in the supply of recuperative hot blast installations and cupolas for blast furnaces and steel works and steel pre-melting plant. 
1961 Demand for economisers from the electricity industry had fallen away and no contracts were expected for delivery in 1962 or 1963
By 1962 Henry Hargreaves Ltd was a subsidiary
1968 Acquired a small company, Thermal Efficiency, from its German owners
1969 Senior Group recognised that the business was much more dependent on steel tubing, air handling and engineering work than economisers, for which the future prospects did not look so good
c.1970 Name changed to Senior