| Adrian Charles Morris | Director | 16 Jun 2008 | 3 Nov 2009 | British | 59 years |
| Ann Louise Finlayson | Director | 1 Dec 2008 | 7 Nov 2013 | British | 71 years |
| Bryan Andrew Halliday | Director | 1 Feb 2015 | 2 May 2017 | British | 56 years |
| Christopher Howard Morrison | Director | 1 Mar 2016 | 10 Jan 2018 | British | 54 years |
| Claire Miles | Director | 1 Feb 2013 | 1 Jan 2014 | British | 54 years |
| Gab Saturnio Barbaro | Director | 1 Jan 2014 | 28 Jan 2016 | Italian | 55 years |
| Gearoid Martin Lane | Director | 16 Nov 2007 | 30 Oct 2012 | Irish | 62 years |
| Holland Elizabeth Troy | Director | 16 Nov 2007 | 16 Jun 2008 | American | 53 years |
| Jonathan Simon Tudor | Director | 31 Dec 2019 | 3 Jul 2020 | British | 55 years |
| Lucy Jean Darch | Director | 3 Nov 2009 | 29 Jul 2015 | British | 56 years |
| Nicholas John Park | Director | 5 Mar 2019 | 31 May 2020 | British | 48 years |
| Pamela Conway | Director | 1 Feb 2016 | 17 Oct 2016 | British | 56 years |
| Rebecca Jane Triffitt | Director | 5 Mar 2019 | 1 Feb 2021 | British | 46 years |
| Stephen Thomas Samuel Salisbury | Director | 13 Oct 2016 | 31 Dec 2019 | British | 46 years |
| Virginia Katharine Croft Graham | Director | 1 Dec 2008 | 31 Jan 2010 | British | 72 years |