Hi,
I had virtually the same bike. Not an easy bike, really frame to find info on.
Mine was originally built up with 7 speed Ultegra. This I updated to a 10 speed Campy Centaur group set. The rear stays had a enough spring to take the wider axle. Also had to update the fork to an Evo carbon The original came a cropper when I hit a pot hole stripping the thread. A friend at Raleigh then repainted it in pearlescent red. It eventually succumbed to the dread rust, the rear stay corroding near the drain hole.
I had some great times on my Peugeot including a month around Chambrey riding many of the historic TdF cols.
Great to see some pictures.
p.s. the saddle in the picture just worked at this odd angle