Surprised Peugeot insisted on using the Vitus style grub screw seatpost anchoring method on such a late model bike. It' not that good a design IMO.
If the the design is the same as th Vitus, what you should maybe try to do is find the proprietary seatpost that was usually provided with the frames. The later model Vitus frames used an aluminum post of 25 and 23mm diameters made by Rubis. They machined a flat vertical strip on the back of the post on which the grub screw that had a pivoting bearing tip with a flat on it too, contacted the flat strip area on the back of the post. This distributes the pressure from the grub screw on a bigger area so tht denting is minimized. I suspect Peugeot also sold these frames with a simlar seatpost. Otherwise, you will end up with deeper dents on your posts and it might not be as secure as you need it to be.

Chombi