56% John Beddoes School , Presteigne 52% Ysgol Maes y Dderwen , Ystradgynlais 49% Ysgol Bro Ddyfi , Machynlleth (Bilingual) 42% Newtown High School , Newtown All are substantially out-performed by the county's leading independent school - Christ College, Brecon . In 2007 91.3% achieved grades A - C in GCSE