Raptor ID

I saw this bird, asleep I believe, at Yorkshire Wildlife Trust Staveley.  Unfortunately because of the surrounding trees and undergrowth I struggled to get it in sharp focus nor get a front view. Note the black head, yellow base to the beak and what appears to be white/pale underside. The white patches in the back feathers are also interesting. I am having difficulty identifying this bird and would welcome some help in doing so. Is it a Peregrine? This is my best guess at the moment.