| HCOGAS500050 | Risks |
| HCOGAS500100 | Notifications |
| HCOGAS500150 | Action in the Cumbernauld Accounting Centre |
| HCOGAS500200 | Action by audit team |
| HCOGAS500250 | Revenue Traders records |
| HCOGAS500300 | Returns on Form C&E 930A |
| HCOGAS500350 | Errors in returns |
| HCOGAS500400 | Further checks on gas delivered without payment of duty |
| HCOGAS500450 | Motor vehicle conversion |
| HCOGAS500500 | Action on receipt of references |
