For what it counts and based on your initial message you may not need to replace the polycarbonate just the rubber seals and maybe underside spacer strips if any.
Plastic conservatory roof leaking.
Repair tape maybe your best best if you ve seen that the cause of the leak is a physical hole to your plastic conservatory roof.
Thoroughly clean the area and fit specialist htg adhesive flashing to bridge the problem area.
Leak below roof vent due to failed poor mutin bar seal above or below.
Slipped or cracked conservatory panels can be repositioned resealed or replaced entirely to eliminate leaks and restore the watertight seals of a once leaking conservatory roof.
Leak through the roof vent.