A GRANDMOTHER who used a schoolboy as her "sexual plaything" has been jailed by judges who overturned her "unduly lenient" suspended sentence.Three top judges at the Court of Appeal in London replaced the non-custodial term with three-and-a-half years immediate imprisonment for gran Marie McCarthy, 62, who committed sexual offences against a 15-year-old 30 years ago.The judges agreed with argument by Solicitor General Robert Buckland that a sentence of 21 months, suspended for two years, which was ...