Schedules for the next round of TV coverage of the 2008 Charterhouse Heritage GT Car Challenge have been announced.Highlights of the races at Silverstone on 16/17 August will first be screened on Sky Sports Extra during the early evening of Tuesday 9 September, with a further five repeat broadcasts.The provisional broadcast schedule is as follows:Tuesday 9 September at 18.00 on Sky Sports XtraTuesday 9 September at 23.30 on Sky Sports XtraWednesday 10 September at 02.30 on Sky Sports 3Wednesday 10 September at 09.30 on Sky Sports 2Wednesday 10 September at 14.30 on Sky Sports XtraWednesday 10 September at 17.30 on Sky Sports 2