| INDUSTRIAL SWITCHGEAR LIMITED | Redditch | 1959 | Total exemption (full) |
| BOARDMAN TRANSFORMERS LIMITED | Ulverston | 1959 | Total exemption (full) |
| LPA INDUSTRIES LIMITED | Saffron Walden | 1959 | Audit-exempt subsidiary |
| PRECISION ENGINEERING LIMITED | Gwent | 1959 | Small company accounts |
| SIEMENS ENERGY LIMITED | Newcastle upon Tyne | 1959 | Full accounts |
| IMAGIN INTERNATIONAL LIMITED | Houghton Regis | 1959 | Unaudited abridged |
| DELMATIC LIMITED | London | 1959 | Total exemption (full) |
| TROLEX LIMITED | Cheshire | 1959 | Medium company accounts |
| ANGLO CARBON & CONTACTS LIMITED | Pudsey | 1960 | Total exemption (full) |
| HAMLIN ELECTRONICS EUROPE LIMITED | Norwich | 1961 | Small company accounts |
| OLSON ELECTRONICS LTD | Middlesex | 1961 | Small company accounts |
| STORK THERMAL EQUIPMENT LTD | Southport | 1961 | Full accounts |
| CONTROL ENGINEERING LIMITED | Witham Essex | 1961 | Total exemption (full) |
| POSSUM LIMITED | Aylesbury | 1961 | Small company accounts |
| ELMATIC (CARDIFF) LIMITED | Cardiff | 1962 | Unaudited abridged |
| ACRASTYLE LIMITED | Ulverston | 1962 | Full accounts |
| ENERSYS LTD. | Newport | 1962 | Full accounts |
| TRUVOX INTERNATIONAL LIMITED | Southampton | 1962 | Group accounts |
| SCHNEIDER ELECTRIC CONTROLS UK LIMITED | Telford | 1962 | Full accounts |
| CONTROL TECHNIQUES DYNAMICS LIMITED | Andover | 1962 | Full accounts |
| TRITON ELECTRONICS LIMITED | Essex | 1963 | Total exemption (full) |
| ELMDENE INTERNATIONAL LIMITED | Portsmouth | 1963 | Full accounts |
| HEMCO POWER & CONTROL SYSTEMS LTD. | Eastleigh | 1963 | Total exemption (full) |
| ALBRIGHT (ENGINEERS) LIMITED | Whitchurch | 1963 | Small company accounts |
| BACKER HEATROD LIMITED | Bolton | 1963 | Medium company accounts |
| NUMATIC INTERNATIONAL LIMITED | Camberley | 1963 | Group accounts |
| HARTLEY & DARK ELECTRIC LIMITED | Orpington | 1963 | Total exemption (full) |
| DESIGNPLAN LIGHTING LIMITED | Sutton | 1963 | Medium company accounts |
| ELECTROSONIC LIMITED | Dartford | 1964 | Full accounts |
| AUTO MARINE CABLES LIMITED | Worsley | 1964 | Medium company accounts |
| MARSHALL AMPLIFICATION PLC | Bletchley | 1964 | Full accounts |
| CWMBRAN ELECTRICAL SERVICES LIMITED | Cwmbran | 1964 | Total exemption (full) |
| LEEDS TRANSFORMER CO.LIMITED | Leeds | 1964 | Total exemption (full) |
| ENCAPSULITE INTERNATIONAL LIMITED | Leighton Buzzard | 1964 | Total exemption (full) |
| MELLOR ELECTRICS LIMITED | Blackburn | 1964 | Total exemption (full) |
| ADDLESTONE ELECTRONICS LIMITED | Bisley, Woking | 1964 | Total exemption (full) |
| HORWICH ELECTRONIC LABORATORIES LIMITED | Works Bolton | 1964 | Total exemption (full) |
| VERIVIDE LIMITED | Leicester | 1964 | Total exemption (full) |
| AUTAC PRODUCTS LIMITED | Macclesfield | 1964 | Total exemption (full) |
| ESS PEE FABRICATIONS LIMITED | Lancashire | 1964 | Total exemption (full) |
| ANGLIA TRANSFORMERS LIMITED | Bordon | 1965 | Total exemption (full) |
| INSULATED TOOLS LIMITED | W. Sussex | 1965 | Total exemption (full) |
| JOHN H. RUNDLE LIMITED | Lincs | 1965 | Total exemption (full) |
| HOLOPHANE EUROPE LIMITED | Milton Keynes | 1965 | Full accounts |
| PENNY & GILES CONTROLS LIMITED | Christchurch | 1965 | Full accounts |
| ANORD MARDIX (UK) LIMITED | Kendal | 1966 | Full accounts |
| BROYCE CONTROL LIMITED | — | 1966 | Total exemption (full) |
| KENWOOD LIMITED | Hampshire | 1966 | Full accounts |
| D. BENSON (CONTROLS) LIMITED | West Yorkshire | 1966 | Total exemption (full) |
| STARLIGHT XPRESS LIMITED | Thatcham | 1966 | Total exemption (full) |
| TRIDONIC UK LIMITED | Basingstoke | 1966 | Full accounts |
| DEEBRIDGE ELECTRICAL ENGINEERS LIMITED | Aberdeen | 1966 | Small company accounts |
| THE ELECTRIC ACTUATOR CO LIMITED | Halesowen | 1966 | Total exemption (full) |
| W.H. KEMP (ELECTRICS) LIMITED | Westbury | 1967 | Total exemption (full) |
| COLLINGWOOD LIGHTING LIMITED | Sywell, Northampton | 1967 | Full accounts |
| HITEK POWER LIMITED | Littlehampton | 1967 | Full accounts |
| D.G. CONTROLS LIMITED | Derby | 1967 | Total exemption (full) |
| JOHNSON ELECTRIC INTERNATIONAL (UK) LIMITED | Newport | 1967 | Full accounts |
| KESTRAL CONTROLS LIMITED | Glasgow | 1967 | Total exemption (full) |
| VERTIV INFRASTRUCTURE LTD | Bedford | 1967 | Full accounts |