Charlotte Sharpe went to boarding school and had assumed her own children would too. But during a tour of a prospective school for her daughter, she walked into a dormitory, saw the familiar row of single beds and knew she couldn’t do it. “When the kids were at prep school, they tried a bit of flexi-boarding, which they loved because it was like a lovely sleepover with all their best friends. But when we were in that dorm, I just felt sick,” says the mother of three from Sussex.