Mullard Wireless Service Co
of "Mullard House", Denmark Street, London, WC2. Telephone: Gerrard 9668. Cables" "Radiovalve, Westcent, London". (1929)
of Century House, Shaftesbury Avenue, London, WC2. Telephone: Gerrard 7777 (Private Exchange). Cables: "Radiovalve, Phone, London". (1947)
1926 Mullard Wireless Service Co, at the suggestion of Charles Orr Stanley, published a quarterly magazine promoting home construction of 4-valve radio sets, using valves made by Mullard Radio Valve Co
1929 Stanley Mullard resigned as managing director but continued as chairman
For more information see Mullard
1929 Listed Exhibitor - British Industries Fair. Distributors of Mullard Master Radio Valves, Pure Music Speakers,"Permacore" Transformers; H. T. Supply Units, Battery Chargers, Grid Leaks, Resistances, and Condensers; Transmitting, Modulating, and Rectifying Valves and other Radio Apparatus. (Stand No. MM.25) 
1938 Mullard apparently displayed a laboratory demonstration television at the Radiolympia, incorporating their own fifteen inch magnetically deflected C.R.T. Like the television, the C.R.T. does not seem to have entered production.
1939 Mullard returned to Radiolympia with two commercial televisions. The show took place in the second half of August, but finished prematurely due to the outbreak of World War II. There is no mention of any earlier Mullard televisions and the two that were displayed at Radioympia may not have entered production.
1947 British Industries Fair Advert for Mullard Products: Valves and Electronic Tubes for Communications; Scientific and Measuring Apparatus; Control Equipment; R.F. Heating and other industrial applications; "Ticonal" Permanent Magnets; High Stability Resistors; Air Dielectric Trimming Capacitors; Industrial Electronic Measuring and Indicating Apparatus; Electro-Acoustic Equipment; Amplifiers; Microphones; Loud Speakers; Horns and Accessories. (Music and Radio Section - Olympia, Ground Floor, Stand No. A.1018)
- and Manufacturers of Industrial and Transmitting Valves, Electronic Measuring Apparatus. (Olympia, Ground Floor, Stand No. C.1538) 
1948 On the 22nd April, Mullard Wireless Service Co officially changed its name to Mullard Electronic Products to reflect the company's expansion of activities beyond that of purely "wireless" and into industrial, scientific and communications activities.
Sources of Information
-  The Valve Page Website