It used to be quite commonplace for wealthy families to hire a “Private Chef” to take care of their needs. A “Personal Chef” service is often an individual who serves many families, going into their homes and preparing meals for one to two weeks or more at a time, charging them for the cost of ingredients and for the labour separately.
A growing field now is the “Personal Chef Caterer” who operates without a “bricks & mortar” commercial kitchen, but arranges a menu, shops that day and then cooks all the courses from scratch in the clients home.
This way the client is not buying a prepared food, but enlisting a service, therefore only GST is charged, and of course the chef has much less overhead costs than a caterer.
The difference to a client is that you are getting a professional who specializes going into many sorts of kitchens, that person can think on their feet, and is able to work under pressure doing everything “A la Minute” (to order).
Large catering companies, do most of the prep in commercial kitchens under the supervision of an experienced catering chef and then send the food partially assembled, so to speak, and then often rely on semi-professionals to re-heat the food on-site. They operate this way in order to guarantee consistency, and also because of time restraints and food cost concerns.