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- GARETH O'BRIEN LTDActive - Proposal to Strike off- 09563941 - Incorporated on 28 April 2015 
- O'BRIEN&WILSON LTDDisolved- 08945281 - Dissolved on 12 September 2023 
- O'BRIEN SEARCH LTDDisolved- SC631445 - Dissolved on 21 June 2022 
- BARNET O' BRIEN LLP- OC323689 - Incorporated on 6 November 2006 
- KJ O'BRIEN LIMITEDActive - Proposal to Strike off- 04136109 - Incorporated on 5 January 2001 
- SAWYER O'BRIEN LLP- NC000553 - Incorporated on 30 September 2009 
- BRIEN & BRIDGE LTD- SC709940 - Incorporated on 21 September 2021 
- RICHARD RICHARD LIMITEDDisolved- 13998117 - Dissolved on 12 September 2023 
- PM O'BRIEN LIMITEDActive - Proposal to Strike off- 10175022 - Incorporated on 11 May 2016 
- BONITA O'BRIEN LTD- 12398880 - Incorporated on 13 January 2020 
- R.J. O'BRIEN (UK) LIMITEDDisolved- 04299065 - Dissolved on 25 April 2023 
- A. O'BRIEN SPINES LTD- 09273931 - Incorporated on 21 October 2014 
- E O'BRIEN IT LIMITEDActive - Proposal to Strike off- SC558335 - Incorporated on 22 February 2017 
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