Vintage Peugeot fixed conversion

Bike newbie here...
Great looking bike, fairly strange question but i have a super competition frame aswell except the bolt used to tighten the seat tube was missing when i got it. Any chance you could tell me size of bolt/thread so that i can get a new one or is it a one size fits all situation?

As far as I know, they're pretty standard. A proper bike shop (one that smells like oil, not one that's full of crabon goods and smells like polish) will have a replacement.

This bike is schmexeh. Really lovely conversion.

But... MY EYES!! Those brake levers... so polished and shiny. They gleams and burns me!! WTF did you shine them up with?!?? They're amazing. :-)