Got to agree with Guppy there, there's instructing and there's teaching. I've been lucky in having great teachers apart from one who I did some field landing checks in a Grob with once. He was bloody hopeless. No doubt a great pilot etc but not a teacher. In fact when we landed I tore him off a strip for his lack of teaching ability and I passed the checks with flying colours. (I'm a teacher myself). I left him with his jaw hanging on the ground.