| UK Company Name | Partial Address |
| O H Hewett Limited | Southgate, London |
| O'Hagan & Murray Limited | Newry, Down |
| O'Hagan Civils Limited | 153-157 Cleveland Street, London |
| O'Hagan Construction Limited | 63 Newry Road, Rathfriland |
| O'Hagan Contracts Limited | STANMORE, MIDDLESEX |
| O'Hagan Design & Build Limited | 153-157 Cleveland Street, London |
| O'Hagan Developments Limited | Newry, Co Down |
| O'Hagan Electrics Limited | DUNGANNON, CO TYRONE |
| O'Hagan Group Limited | Rathfriland, Newry |
| O'Hagan Properties Limited | MANORHAMILTON, CO. LEITRIM |
| O'Hagan Property Limited | Newry, Co Down |
| O'Halloran & O'Brien Limited | MORDEN, SURREY |
| O'Hanlon & Farrell Contracts Ltd | NEWRY, COUNTY DOWN |
| O'Hanlon & Farrell Electrical Limited | Newry |
| O'Hanlon & Farrell Holdings Limited | NEWRY, CO DOWN |
| O'Hanlon Bros Construction Limited | Coalisland, Co Tyrone |
| O'Hanlon Tyres (N.I.) Ltd | KILREA |
| O'Hara Bros. Aggregates Ltd | HATFIELD, HERTFORDSHIRE |
| O'Hara Bros. Surfacing Limited | HATCH END, MIDDLESEX |
| O'Hara Property Investment Holding Company Limited | Hatch End, Middx |
| O'Hara Transport Limited | PINNER, MIDDLESEX |
| O'Hare & Mcgovern Limited | NEWRY, CO.DOWN |
| O'Hare Construction Ltd | Newcastle, Down |
| O'Hare Developments Limited | CARNBANE, NEWRY |
| O'Hare Steel Limited | MAYOBRIDGE, NEWRY |
| O'Hares Drumaness Ltd | NEWRY, COUNTY DOWN |
| O'Hares Rathfriland Limited | NEWRY, DOWN |
| O'Hares Supermarket Limited | Newry, County Down |
| O. Heap & Son (Derby) Limited | DERBY, DERBYSHIRE |
| Oh Assist Limited | 2 Hayland Street, Sheffield |
| Oh My Dog! Ltd | BECKENHAM, KENT |
| Oh My! Productions Limited | BASILDON, ESSEX |
| Oh Sew Sweet Ltd | South Somercotes, Louth |
| Oh So Lean Ltd | Kilkeel, Co. Down |
| Oh Yeah Music Centre | BELFAST |
| Ohes Environmental Limited | Harrogate, North Yorkshire |
| Ohi Acg Holdings Ltd | 50 BROADWAY, LONDON |
| Ohm Engineering Ltd | Clogher, Co Tyrone |
| Ohmg Ltd | Newry, Co. Down |
| Ohob Group Limited | MORDEN, SURREY |
| Ohob Holdings Limited | MORDEN, SURREY |