Driving for manufacturers?

[captain jack]

A friend and I were discussing this last night and was wondering if anyone knew what qualifications the drivers have that manufacturers use for either staff training or safe hands to demonstrate their vehicles? We were thinking top end stuff - his wife was involved in some Aston Martin PR recently and said that their drivers were freelance but seemed to have a great time driving Astons. She also said they were pretty polished guys and very professional - but didn't just do the showy stuff but also instructed Aston staff to drive product safely.
Obviously if either of us were involved in her PR we would have asked the guys directly but we aren't so wondered if anyone here knew how that would work?