If the deeds do not indicate responsibility, have a discussion with your neighbour. If you are both unsure, ask other neighbours as there may be an unspoken pattern you can follow.
Try to come to an agreement as to who owns the fence and, thus, is in charge of replacing the panels. We understand that this is not always as easy as it sounds and sour relationships do occur between neighbours. This is where it becomes a little more tricky. If there is a dispute, we recommend talking to your local Citizen’s Advice Bureau.
What to do next...
If it is clear that the boundary is yours, it is wise to let your neighbour know about any renovation, repair or replacements you are planning before you begin.