Need help with starting Caterham series, I must have a case of the stupids.

I would like to start the default Caterham series with all the makes available for the AI to be allocated at random. However if I try to start a season I can't see where to choose which type of Caterham I want to drive.

I would like to use the Caterham Supersport but on the car select screen it just has a list of driver names but no mention of which car I will be getting. If I choose any of the cars I get allocated one of the other variants.

Am I allocated a car at random or is there a way to choose which Caterham I want?