In reply to Chris Craggs:
Hi Chris. La Mosca starts about 3-4m to the right of Perrel el cacaolat, goes up and trends left towards that route a bit then steps right across the wall then up to a separate lower off. Its very good, maybe **and the grade is 5+ overall maybe just 6a on the crux step right. By the way Arnauet seems hard for 6a, probably 6a+ and there is a bolt missing high up on the route last time I looked.