Is it possible to site grade 1 piano exam without having a teacher. (please read whole thing)?

Ok well i just sat my piano grade 1 but got nervous and it wen tbad... i have not go tmy results back yet but i am positve i have failed (i miss played 2 scales, 1 arpedgio and half of one of my pieces) And lets get this straight... i hate piano but i was motivated to p this as if i did i get to quite it (pushy parents) i do try to have a positve attitude to it but anyway that isn't the point... i want ot stop having lessons as i feel i know everything i need to especialy after experiencing the exam and feel i can practise at home in my own time as if i did have a teacher... piano lessons cost around �150 per term which could go to other things so can i take the exam without having a teacher and if so how do i enter myself into an exam (the shakespeare one in derby to be precise if that helps) My piano teacher said the next exam is in november but i don't see why.