So I was just in the office kitchen (making a coffee (sadly Terry Tate's rules on "kill the joe; make some mo' are not yet in force here) when I chanced to look out of the window and see a red-tail thermalling. It seemed to be working harder than usual and kept breaking into full on flapping mode for no apparent reason when I saw a second bird soaring above (pretty much a speck at this point - my bins stay in the car, not the office). All of a sudden the second bird starts dropping fast and resolves into a Peregrine which makes a full on agressive stoop on the red-tail which looks to evade and with the peregrine closing very fast both drop out of view and don't return.
The kettle has just boiled. Nice coffee break!