A HEADTEACHER this week urged the Government to cut the state benefits of parents whose children persistently play truant. Dame Jean Else, who has dramatically reduced truancy at Whalley Range high school for girls in Manchester since tking over in 1994, believes the threat would virtually eliminate the problem. Parents can be fined up to pound;1,000 if their child continually fails to attend lessons, but many cannot afford the fines which are often written off.