| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| BLENHEIM PALACE HERITAGE FOUNDATION | 09430048 | 22/09/2022 | Silver |
| HISTORIC HOUSE HOTELS LIMITED | 01440570 | 24/09/2008 | Gold |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| ASSOCIATION OF INDEPENDENT MUSEUMS | 01350939 | 16/06/2011 | 20/06/2014 | Gold |
| INTERNATIONAL INSTITUTE FOR CONSERVATION OF HISTORIC AND ARTISTIC WORKS(THE) | 00481522 | 18/01/2013 | 28/01/2019 | Bronze |
| NATIONAL TRUST (ENTERPRISES) LIMITED (THE) | 01083105 | 11/01/2006 | 30/06/2014 | One Red Flag |
| NATIONAL TRUST (RENEWABLE ENERGY) LIMITED | 08763161 | 05/11/2013 | 30/06/2014 | One Red Flag |
| THE ENGLISH HERITAGE TRUST | 07447221 | 01/03/2015 | 31/12/2023 | Amber |