Jeremy Clarkson drives two new Aston Martins - the DB7 Volante convertible and the V8 coupe. He travels to the cars' Buckinghamshire base to ponder the future of this great British marque. Quentin Wilson delivers the results of Top Gear's third annual survey, conducted jointly with an American market research organisation, in which viewers assess the performance of their three-year-old cars. The 14,000 replies are compiled into a league table rating 72 different models.