| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| The Northern Horticultural Society | 02174290 | 07/09/2004 | Dissolved |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| CASTLE HOWARD ARBORETUM TRUST | 03006258 | 21/11/1997 | 01/05/2002 | Gold |
| CLDN PORTS HUMBER LIMITED | 00052665 | 01/01/1998 | 31/12/2000 | Silver |
| GMG INVESTCO 2 LIMITED | 03673138 | 21/11/2003 | 01/05/2008 | Dissolved |
| GMG INVESTCO 3 LIMITED | 04768840 | 21/11/2003 | 31/05/2007 | Not Trading |
| GUARDIAN MEDIA GROUP PLC | 00094531 | 29/04/1999 | 01/05/2008 | Silver |
| R.H.S. ENTERPRISES LIMITED | 01211648 | 21/06/2006 | 21/06/2009 | Bronze |
| RATHBONES GROUP PLC | 01000403 | 01/06/1999 | 22/12/2008 | Silver |
| RATHBONES INVESTMENT MANAGEMENT LIMITED | 01448919 | 28/02/2000 | 14/11/2005 | Silver |
| THE DENDROLOGY CHARITABLE COMPANY | 02816525 | 28/06/2001 | 22/05/2018 | Dissolved |
| THE FOUNDATION AND FRIENDS OF THE ROYAL BOTANIC GARDENS, KEW | 02499006 | 17/05/2011 | 08/11/2016 | Gold |
| THE TEST AND ITCHEN ASSOCIATION LIMITED | 00413521 | 31/12/2010 | 17/12/2020 | Gold |