Gregg Wallace visits the Ercol factory in Buckinghamshire, an area associated with furniture making since the 19th century.We Brits spend a staggering £300 million pounds each week on furniture, and Gregg is following the production of one of this factory's best sellers, the Windsor chair. Starting life as ash trees from European woodlands, they're cut, drilled, steamed, curved and sanded until they're ready for delivery to shops and homes.Meanwhile, Cherry Healey investigates how sitting too much could be very bad for our health, and she helps to manage a sustainable woodland at the Rushmore Estate in Wiltshire. And historian Ruth Goodman discovers how utility furniture made during the Blitz is still influencing the designs we buy today, as well as learning how a humble British carpenter went on to make the most expensive piece of furniture ever sold.