Persuading a secondary school to take me on for a GTP course?

To get on a years teacher training course for PE or possibly primary there is a course called GTP- you get paid to study compared to the PGCE where you pay 3000 pounds. But you need a school to sponsor you. How can I persuade a school to sponsor me? I am/have done two weeks work experience in two different schools, one private, one state. How about other schools as well?