Had a quick look through all the levels, no luck yet. Going to go back and spend more time on each!
Found it. Chapter 5.
> Found it. Chapter 5.
It’s on the top of a rock right at the start of the mission, turn around and look up at the rocks.
Here’s the video for your viewing pleasure: http://www.youtube.com/watch?v=i0CZJ9-y48M