Heatly-Gresham Engineering Co
From Graces Guide
of Bassingbourn Iron Works, Royston
of Letchworth, and of 110 Cannon Street, London.
1903 Began the building of the Rational engine at Bassingbourn in 1.5, 3 and 6 hp sizes 
1904/5 Moved to Letchworth and built the first factory at Letchworth, called Gresham Iron Works. Manufactured railway materials, especially the component parts of the continuous automatic vacuum brake, and industrial oil-engines.
An associate of Gresham and Craven of Manchester
1930s Ceased trading
Sources of Information
- A-Z of British Stationary Engines by Patrick Knight. Published 1996. ISBN 1 873098 37 5
- The Times Mar 10, 1931