We were feeding, grooming and exercising the horses on our farm one hectic Saturday morning when a car pulled into the yard. A woman wound down the window to talk to my husband, Michael.

'We heard that you have children here to help on Saturday mornings,' she said. 'We wondered if you would have our daughter Sophie?

'Her father and I are very worried. She's 13 and has stopped talking — she hasn't spoken a word for two years. She likes reading books about horses and we heard about you.'