Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 144,279 pages of information and 230,174 images on early companies, their products and the people who designed and built them.
D. H. Bonnella and Son of 46-48 Osnaburgh Street, London, NW1
founded by David Hunter Bonnella
1937 Manufacturers of aircraft and electrical accessories. 
1939 See Aircraft Industry Suppliers
The company made many small low voltage switches and was a supplier to Ford among others.
In 1963 the company became the manufacturer of Cherry microswitches under licence from Cherry.