 Complete the following phrase:  Chelmsford City known as Great Leighs at the time was developed and owned by entrepreneur John Holmes and his son, Jonathan. It aimed to exploit potentially the largest unserved market in British horseracing. Overall there is slightly more than one racecourse per million people in Great Britain, but there was no racecourse in Essex population 1.6 million, in east London formerly in part, part of Essex or in the neighbouring county of Hertfordshire population 1 million. The new course is only from Newmarket, the largest racehorse training centre in Britain. The course is laid out as an left-handed Polytrack oval, with a home straight. The 10,000-capacity grandstand was used at the 