| Company | Timeline | Status | |
| Ila-Spa Limited Director • Architect | 30 Sep 2015←6 Years→18 Mar 2022 | Dissolved | |
| Simpson And Company Limited Director • Project Manager | 21 Jun 1996←29 Years→Current | Active | |
| John Simpson & Partners Limited Director • Engineer | 26 Apr 1993←32 Years→Current | Active | |
John Simpson & Partners (Paternoster) Ltd Secretary • Unreported | 6 Sep 1992←21 Years→25 Mar 2014 | Dissolved | |
| John Simpson & Partners Limited Secretary • Unreported | 19 Sep 1991←34 Years→Current | Active | |
