Graham I’d be amazed if indeed that was a Hen Harrier. Not aware of any captive birds. MostIn our garden we see Green Woodpeckers and within a 15 min drive we can see Red Kites (which I suppose are common). We have also had deer in our garden twice since moving in in 2018. Badgers common in our neighbourhood too, never seen any in my life until a couple of years ago.
In other news in Q4 last year I saw a Hen Harrier in SW1 which was being controlled by a falconer who had been instructed by the Council to help drive away pigeons. Apparently such raptors strike a primordial fear in pigeons... I also red that the HH is endangered in this country so makes sense that the one I saw was not in the wild.
likely to be a Harris Hawk (not native) for controlling pigeons. Happy to be corrected.