I picked up a similar frame from a freecycler. Late 80's with 531 tubing. I thought I'd restore it to the original spec but it has the notorious awful helicomatic hub. Yours might be the same. I'm going to powdercoat it and fit modern cheap components to have a lightweight commuter. You're lucky to have a seatpost - I don't and it's a weird size but evrything else is "British" sizes. Couple of good links here and if it's still got the pape sticker you'll ID it pretty quickly. There are a few Peugeot fanatics on www.retrobike.co.uk will tell you it's nothing special but in it's day was a low to mid range model.