| Colin Rossiter | Director | 5 Jul 2013 | 1 Jun 2018 | British | 70 years |
| Daniel Marinus Maria Vermeer | Director | 23 Aug 2017 | 1 Mar 2021 | Dutch | 45 years |
| David Allan Valks | Director | 25 Jan 2017 | 1 Jun 2018 | British | 60 years |
| David Joyce | Director | 5 Dec 2012 | 6 Dec 2017 | British | 49 years |
| David Sheridan | Director | 5 Dec 2012 | 5 Jul 2013 | British | 64 years |
| David Taylor | Director | 5 Jul 2013 | 23 Dec 2016 | British | 75 years |
| Edward Arthur Wilson | Director | 6 Dec 2017 | 7 Jan 2019 | British | 61 years |
| Fabio D'alonzo | Director | 5 Dec 2012 | 22 Jul 2015 | Italian | 50 years |
| Hannah Holman | Director | 1 Mar 2021 | 1 Oct 2024 | British | 46 years |
| James Michael Douglas Thomson | Director | 5 Dec 2012 | 5 Jul 2013 | British | 60 years |
| Jennifer Louise Crouch | Director | 22 Jul 2015 | 26 Jul 2017 | British | 39 years |
| Joanne Stonehouse Fyfe | Director | 1 Mar 2021 | 22 Oct 2025 | British | 60 years |
| Joseph Davis | Director | 27 Aug 2019 | 8 Feb 2021 | British | 36 years |
| Kenneth John Simpson | Director | 26 Apr 2017 | 6 Dec 2017 | British | 61 years |
| Kevin Brown | Director | 23 Sept 2015 | 26 Apr 2017 | British | 50 years |
| Paul Ellis Gill | Director | 6 Dec 2017 | 27 Aug 2019 | British | 51 years |
| Philip Peter Ashbrook | Director | 9 Jan 2019 | 25 Jan 2023 | British | 66 years |
| Robert Alistair Martin Gillespie | Director | 26 Jul 2017 | 1 Mar 2021 | British | 36 years |
| Sion Laurence Jones | Director | 5 Dec 2012 | 23 Aug 2017 | English | 52 years |
| William James Haughey | Director | 5 Dec 2012 | 23 Sept 2015 | British | 52 years |
