| Company | Timeline | Status | |
| Beyond The Brink Limited Director • Designer | 3 Feb 2000←25 Years→Current | Active | |
| Clinical Practice Limited Director • Designer | 30 Dec 1999←25 Years→Current | Active | |
| Marks Creative Limited Director • Designer | 9 Jul 1996←29 Years→Current | Active | |
| Marks Creative Limited Secretary • Unreported | 9 Jul 1996←29 Years→Current | Active | |
| Hanington Limited Director • Illustration Design Consultant | 19 Dec 1991←33 Years→Current | Active | |
The Committee For The Accreditation Of Medical Illustration Practitioners Director • Designer | 15 Nov 1991←4 Years→10 Jul 1996 | Dissolved | |
| Marks Limited Secretary • Unreported | 23 Jun 1991←34 Years→Current | Active | |
| Marks Limited Director • Illustrator & Design Consultant | 23 Jun 1991←34 Years→Current | Active | |
| Medical Artists' Association Of Great Britain Director • Design Illustration | 30 May 1991←4 Years→11 Apr 1996 | Active | |
