I have a Peugeot Ventoux of 1980s vintage. I have lost the clamp with which the seat is mounted to the seat bar embedded in the frame. The clamp holds the two thick wires under the seat and is secured by a bolt. All this rest on a grooved semi circular sunken arch on top of the hollow circular that goes into the frame. Can any one point me in the right direction as to where I can get a replacement clamp. Would also appreciate any other modification solution. Can send pix if needed.