Icelandic sand. Not ideal terrain for drag racing - especially when you're in British cars that weren't really built for off-roading. Chris and Paddy find out what the Vauxhall Chevette and the Rolls-Royce Silver Shadow are capable of when traction is in short supply - and when facing an unexpected competitor in a Range Rover. See the boys' expedition to Iceland in full on BBC iPlayer now. | Top Gear