Finding the Lookup editor
Modifying any drop down list including the Manufacturer/Model/Variant fields is completed using a Lookup Editor. In this case we will use the Vehicle Lookup editor which can be found from the Main Menu under Tools > Lookups > Vehicle
Modifying the Manufacturers Lists
From the Vehicle Lookups Editor click the Manufacturers... button.
You will be presented with a list of all the Manufacturers currently used in Motorcentral.
From here you can Add, Edit or Delete a Manufacturer. When adding or modifying a Manufacturer you have the ability to enter a Display Name as well as select which Manufacturer category this Manufacturer belongs to.
Modifying the Models & Variant Lists
From the Vehicle Lookups Editor click the Models... button. You will be presented with a tree list of all the Manufacturer currently used in Motorcentral. Clicking on the plus [+] icon next to a Manufacturer will display the Models associated with that Manufacturer, and clicking the plus [+] icon next to a Model will display the Variants associated with that Model.
From here you can Add, Edit or Delete a Model or Variant.