I hope the OP ran like hell with their bike. If the shop can't figure out how to measure to figure out which diameter cotter, and don't understand the basic concept of filing a cotter, they're probably not going to properly install the cotters. Wonder if they ever updated the status?
Jsendin I see you saying 8.5mm is the correct size cotter for your Peugeot, I'm curious what year it is, what crank is on it, and whether the BB spindle is original. I swear the 70s-80s era bikes took a 9.0mm cotter, it's what I've shipped out to nearly everyone I've ever gifted to here on BF for their French bikes over the years. Maybe I'm smoking crack, but I've popped enough cotters out in my lifetime you'd think I'd remember.
Edit: I'm also curious how you measured. Did you measure the inner diameter of the hole in the crank and that's where your measure came from?