Thing is I don't know where it is now. Probably another casualty of my parents downsizing from a large Edwardian terrace house in London to a beautiful (but considerably smaller) Georgian cottage in Wiltshire.
But I always loved this chair, so was really pleased to find out what it actually was.
It's the 14 chair by Thonet (available at SCP) and is made from bentwood, which was created by using steam to bend the wood. That was back in 1830 and since then has become a design classic.