Charlotte's table manners

As a Brit I have noticed that Charlotte Byrne has european table manners, eating with knife and fork always in-hand; wheras Wendy, Marty and Jonah have American table manners cut and switch, where the fork is held in the left hand, knife in the right for cutting, then the fork is switched to right hand for eating.
It looks strange that a family member has different eatinge etiquette.