Jeremy Clarkson, Richard Hammond and James May hit Donington in three stripped-out track cars - the KTM X-Bow, the Morgan Three Wheeler and the Caterham R500.Back at the Top Gear airfield, Jeremy recreates the Battle of Britain in an insane aero-engined Bentley and a flame-spitting retro BMW.Blur bassist and professional cheesemaker Alex James is the Star in a Reasonably Priced Car.