It's fairly easy to shove it over, get a socket on the crack, crank it round slowly and push it across as you go. Easy with 2 people. I'd get that back on 
Then, keep an eye on the belt, watch to see if it continues to edge it's way off. If it does, check all pulleys, tensioners etc

Then, keep an eye on the belt, watch to see if it continues to edge it's way off. If it does, check all pulleys, tensioners etc
Diablo Hdi Dturbo and 205 1.9 project - it lives!