| Name | Company Number | Date Appointed | Rating |
|---|
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| GLOBAL INFRASTRUCTURE INVESTOR ASSOCIATION LIMITED | 09668904 | 03/07/2015 | 31/12/2020 | Gold |
| PORTERBROOK HOLDINGS I LIMITED | 09251107 | 17/12/2014 | 15/12/2016 | Bronze |
| PORTERBROOK HOLDINGS II LIMITED | 09251181 | 17/12/2014 | 15/12/2016 | Silver |
| PORTERBROOK INVESTMENTS I LIMITED | 06700588 | 27/01/2015 | 27/08/2015 | Silver |
| PORTERBROOK INVESTMENTS II LIMITED | 07664052 | 27/01/2015 | 27/08/2015 | Dissolved |
| PORTERBROOK INVESTMENTS III LIMITED | 07664057 | 27/01/2015 | 27/08/2015 | Dissolved |
| PORTERBROOK LEASING COMPANY LIMITED | 02912662 | 28/11/2014 | 15/12/2016 | Amber |
| PORTERBROOK LEASING MID COMPANY LIMITED | 07007965 | 28/11/2014 | 15/12/2016 | Amber |
| SCOTIA GAS NETWORKS LIMITED | 04958135 | 27/05/2022 | 13/09/2024 | Bronze |
| SCOTLAND GAS NETWORKS PLC | SC264065 | 27/05/2022 | 13/09/2024 | Silver |
| SGN COMMERCIAL SERVICES LIMITED | 05969465 | 27/05/2022 | 13/09/2024 | Silver |
| SGN CONNECTIONS LIMITED | 05618886 | 27/05/2022 | 13/09/2024 | Amber |
| SGN CONTRACTING LIMITED | 05372264 | 27/05/2022 | 13/09/2024 | Amber |
| SGN EVOLVE NETWORK LTD | 08822715 | 27/05/2022 | 13/09/2024 | Amber |
| SGN FUTURES LIMITED | 13289392 | 27/05/2022 | 13/09/2024 | One Red Flag |
| SGN HEAT NETWORKS LIMITED | 13421041 | 27/05/2022 | 13/09/2024 | Silver |
| SGN LESSONA LIMITED | 11727758 | 27/05/2022 | 13/09/2024 | Bronze |
| SGN MIDCO LIMITED | 11050000 | 27/05/2022 | 13/09/2024 | Bronze |
| SGN PLACE LIMITED | 11245555 | 27/05/2022 | 13/09/2024 | One Red Flag |
| SGN PLEDGECO LIMITED | 11049371 | 27/05/2022 | 13/09/2024 | Gold |
| SGN SMART LIMITED | 05618883 | 27/05/2022 | 13/09/2024 | Silver |
| SOUTHERN GAS NETWORKS PLC | 05167021 | 27/05/2022 | 13/09/2024 | Bronze |