So as I was swapping in the new Osrams that arrived today, my overeager self didn't notice the spring retention screw on one headlight was loose and the spring disappeared into oblivion when I undid the latch. So after freaking out for an hour pondering a few minutes, I improvised by using a key ring. The one on the right LEFT is what I made. It took me all of 15 minutes, and it works perfectly, if a little more pliable than the material the original spring was made of. On the right is what I made. All you need are two needle nose pliers.
Edit: Due to an unexpected brain fart I was unable to tell my arse from my elbow when I made this post. Errors have been rectified.