- DECLAN FROST LIMITED- 11901935 - Incorporated on 23 March 2019 
- DECLAN CONSTRUCTION LIMITEDActive - Proposal to Strike off- 07347392 - Incorporated on 17 August 2010 
- DECLAN DUFFY LIMITEDDissolved- 04284705 - Dissolved on 15 April 2014 
- DECLAN ENGINEERING LTDActive - Proposal to Strike off- 10593157 - Incorporated on 31 January 2017 
- DECLAN SOFTWARE LTDActive - Proposal to Strike off- 10623618 - Incorporated on 16 February 2017 
- DECLAN MCFERRAN LIMITED- NI731526 - Incorporated on 19 July 2025 
- AIDEEN O'HALLORAN ASSOCIATES LIMITEDActive - Proposal to Strike off- 04586765 - Incorporated on 11 November 2002 
- MJ O'HALLORAN SERVICES LIMITEDLiquidation- 10491349 - Incorporated on 22 November 2016 
- O'HALLORAN AND PARTNERS LTD- 15996172 - Incorporated on 3 October 2024 
- DECLAN WARD LIMITEDActive - Proposal to Strike off- 07721070 - Incorporated on 28 July 2011 
- DECLAN KIRK MEDIA LTD- 15469643 - Incorporated on 6 February 2024 
- DECLAN ROSE LIMITEDDisolved- 13794338 - Dissolved on 6 June 2023 
- MICHAEL O'HALLORAN- 7A WALSALL ROAD, FOUR OAKS SUTTON COLDFIELD, BIRMINGHAM, B74 4ND 
- ANDREW O'HALLORAN- Born January 1961 - 21B HAROLD ROAD, UPPER NORWOOD, LONDON, SE19 3PU 
- CATHERINE O'HALLORAN- 5 LINDEN LODGE, 233 WINCHMORE HILL ROAD, LONDON, N21 1QA 
- DYLAN O'HALLORAN- 33 HARBURN AVENUE, DEANS, LIVINGSTON, WEST LOTHIAN, SCOTLAND, EH54 8NQ 
- REBECCA O'HALLORAN- 8 NORWOOD DRIVE, SHEFFIELD, ENGLAND, S5 7BH 
- PETER O'HALLORAN- Born May 1965 - BARNEND, 39 CHURCH LANE, ENENLEY, NORTHAMPTONSHIRE, NN13 5SG 
- Nicole O'HALLORAN- Born January 1963 - 203 London Road, Hadleigh, Benfleet, Essex, United Kingdom, SS7 2RD 
- Shaun O'HALLORAN- Born March 1968 - 5-6 Northumberland Buildings, Queen Square, Bath, Bath And North East Somerset, England, BA1 2JE