I found this in the 'Evening News (London)' dated 12th October 1955: “LEYTONIA RADIO LTD., London's Leading Television and Radio Specialists. 828 High Road, Leyton, E.10. LEYtonstone 1396; 784-786 High Road, Leyton, E.10. LEYtonstone 1396.; 242 Chingford Mount Road, Chingford, E.4 SILverthorne 1233.; 114 High Street, Walthamstow, E.17. LARkswood 8669.”
“LEYTONIA RADIO LTD., London's Leading Television and Radio Specialists. 828 High Road, Leyton, E.10. LEYtonstone 1396; 784-786 High Road, Leyton, E.10. LEYtonstone 1396.; 242 Chingford Mount Road, Chingford, E.4 SILverthorne 1233.; 114 High Street, Walthamstow, E.17. LARkswood 8669.”