New to the UK and have a door in a flat that must come off. It has regular butterfly hinges at the top and bottom, but in the middle of the door is a taut link chain that pulls the door closed. The frame and the door both have two small plates around the chain, which comes through an opening in the center. The plates are anchored with four screws into the wood of the door and the frame. Even after removing the screws on either the door or the frame, the chain does not budge.
Any ideas? Not familiar with these kind of doors, and this one really needs to come off and later be reinstalled.