Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 148,112 pages of information and 233,645 images on early companies, their products and the people who designed and built them.
of Valley Works, Hoddesdon, voltage and power control suppliers
of Waltham Cross
1918 The Claude Lyons Group was founded
1968 A. C. voltage stabilisers 
1985 Acquired the Transformer and Electrical Co Limited (TEC) makers of power transformers, chokes and power supplies.
The Group is still in private ownership.