Young Buzzard or Sparrowhawk

Female spar.

Possibly having a 'go' at its own reflection.

Or more likely having a go a catching a bird that was just at your window feeder ;-)
It's a Sprawk ;-)

Thank you. Excuse my ignorance but what are the distinguishing factors so I can more closely note when she next appears.?

Females are more brown in colour like so

Males are more colourful and smaller lol

However youngsters all look like female to begin with. Females are also larger than males.

It's highly unlikely to get a Buzzard at the window..always a sprawk on the hunt as we supply a fly thru bistro for them ;-)

Brilliant Linda, thank you. I also read somewhere that a sparrowhawk has a white streak above the eye. I zoomed in on one of my many photos and sure enough, it has the white eye marking. There are buzzards nesting in the trees in a field opposite the house which is why I assumed it was one of them. Live and learn.