sentences:  He became stable jockey for trainer John C. Oxley in 1970, but this was not to be a successful partnership, and they split in 1972.After riding freelance for a bit, he was to become first jockey to trainer Sir Mark Prescott in 1974, a partnership which was to prove most enduring and fruitful.George Duffield spent 30 years as stable jockey to Prescott, riding 830 winners for him, including successes in Ireland, France and Belgium.