The Antiques Roadshow makes a return visit to RAF Coningsby in Lincolnshire, where treasures include an aristocratic harp that survived the French Revolution, a beautiful Liberty necklace and a carved piece of wood with a mysterious function. There are plenty of mysteries in the show as jewellery specialist Susan Rumfit hears about a diamond brooch found hidden inside a barometer, and Jon Baddeley reveals the true purpose of a curious piece of carved wood dated 1775, leaving its owner lost for words. Fiona is intrigued by a length of tree that ended up inside a Lancaster bomber on a raid in Norway in the Second World War, while militaria specialist Graham Lay is moved by the remarkable story behind a pair of boots, a child's drawing and a parachute handle. The team admire a Liberty necklace that a young girl plans to wear for her school leaving ball, but a dilapidated French harp that dates from before the French Revolution poses a considerable restoration challenge for its owner. In a programme that has more than a hint of the Battle of Britain spirit, Mark Hill is intrigued to find a pair of wartime propaganda posters printed on hessian sacking, saved from a skip and kept under the owner's bed.