I can't believe none of the other guys got the jist of your question. you don't have a UO-8,you have the matching level of Peugeot touring bike.
the vertical drilled brake bridge is meant to mount a fender and brake with the same bolt. you can make a bracket/brake attachment with a chunk of
al-alloy, a drill and a file. it will in effect be a drop bolt which will be good since I think you're planning to switch to 700c wheels. DO NOT drill a
horizontal hole in your brake bridge! it would then be too weak to fit a brake.