I note that the 1821 three-manual organ at Thaxted (of Gustav Holst fame) is now back in service after a restoration carried out by Goetze & Gwynn. They note on their website that this "is the earliest surviving English church organ which retains all its original parts, and looks, sounds and plays as it did originally."
http://www.goetzegwynn.co.uk/thaxted/specification and photographs:
http://www.npor.org.uk/NPORView.html?RI=N18436