Great - I remember my first one on the M40, I nearly swerved. Saw one last week hovering over the MK boundary at last. Wheeee. I want to see one hovering over my garden.
They were introduced in the Chilterns and I think Rutland way? I have seen them N of MK as well. They are from SPain and breed twice as fast as the Welsh native kind (i.e. every year)
Can't mistake them - a little bigger than a buzzard, great big forked tail and, unlike buzzards tend to hang about nearer to the ground. Often seen playing "chicken" as the M40 crosses the Chilterns (just by that chalk cutting that stars in the Vicar of Dibley credits) - hovering over the motorway, enjoying the draught.
At the other end of the scale, we were in Frosts woburn, just about to leave the car park today - and there was a Goldcrest foraging about, right in front of the windscreen in the cypress hedging. Cute!