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- BRIEN LTDDisolved- 08582463 - Dissolved on 8 August 2023 
- K&A O'BRIEN LTD- 03816457 - Incorporated on 26 July 1999 
- A & S O'BRIEN LTDActive - Proposal to Strike off- SC451340 - Incorporated on 31 May 2013 
- D M O'BRIEN LTD- 12118376 - Incorporated on 23 July 2019 
- C O'BRIEN LTDActive - Proposal to Strike off- 09910506 - Incorporated on 10 December 2015 
- K & J O'BRIEN LTDDisolved- 14994563 - Dissolved on 17 December 2024 
- MR JOHN RICHARD TAYLOR LIMITED- 15648315 - Incorporated on 15 April 2024 
- MR LEE RICHARD ROSCOE LIMITED- 15754419 - Incorporated on 1 June 2024 
- MR JAMES RICHARDSON LIMITEDDissolved- 06920581 - Dissolved on 11 January 2011 
- O'BRIEN VARLEY CONSULTING LIMITEDDisolved- 06373208 - Dissolved on 4 April 2023 
- LJ O'BRIEN LTD- 08082294 - Incorporated on 24 May 2012 
- DF O'BRIEN LTD- 09262077 - Incorporated on 13 October 2014 
- JO O'BRIEN LTD- 08293977 - Incorporated on 14 November 2012 
- KL O'BRIEN LTDActive - Proposal to Strike off- 10268691 - Incorporated on 8 July 2016 
- S O'BRIEN & CO LTD- 10576858 - Incorporated on 23 January 2017 
- O'BRIEN'S (SW) LTD- 14817454 - Incorporated on 20 April 2023 
- DA O'BRIEN LTDDisolved- 12956298 - Dissolved on 1 August 2023 
- O'BRIENS FITNESS C.I.C.Active - Proposal to Strike off- 08633301 - Incorporated on 1 August 2013 
- NF O'BRIEN LTD- NI680541 - Incorporated on 5 July 2021