Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 148,103 pages of information and 233,633 images on early companies, their products and the people who designed and built them.
of Holbro Works, Billet Road, Walthamstow, London, E17. Telephone: Larkswood 4422. Cables: "Dogfish, London"
1934 Patent - Improvements in and relating to surveyors' levelling staves. 
1935 Patent - Improvements in or relating to telescopic drawing board easels. 
1947 Listed Exhibitor - British Industries Fair. Manufacturers of "Holbro" Drawing and Surveying Apparatus for Engineers, Architects and Schools. Drawing Boards, Tee Squares, Set Squares, Straight Edges, Drawing Tables, Surveyors' Levelling Staves, Ranging Poles, Plane Tables and Tripods, etc. (Olympia, Ground Floor, Stand No. A.1037)