| Company | Timeline | Status | |
| Advent Maintenance Services Limited Director • Chairman | 26 Aug 1998←27 Years→Current | Active | |
| Advent Ductwork Systems Ltd Director • Ventilation Engineer | 30 Aug 1991←34 Years→Current | Active | |
| Advent Mechanical Services Ltd Director • Ventilation Engineer | 16 Apr 1991←34 Years→Current | Active | |
