The 40-year-old Scot has been Britain's most successful Grand Prix racer since the legendary Barry Sheene. At his final race in Knockhill in August 2001, more than 20,000 fans turned up to watch Mackenzie and to bid farewell to their local hero. Niall has come a long way from Denny where he would regularly get into trouble for racing round the streets, as well as in and out of the local chip shops, to impress the girls. As an amateur...