Hi TKbird. I can't hear a Marsh Harrier but just wanted to share that a Marsh Harrier is not unexpected inland. They can be seen at plenty of inland water bodies or marsh areas. They're reliably seen at Otmoor, Oxfordshire for example. I hope you get to see one soon.
Another for goshawk. Bulky looking - in the legs as noted by Alan but also the head, beak and body. Out of interest, is the orange eye a safe diagnostic in this neutral light or do you get sprawks with orange eyes too? They always seem yellow to me.
Great photo AFairbairn
Hi Mali. It's a Bald eagle juvenile as you suspect. Big beak, dirty mottled underwings and general appearance. Baldies and Goldies are pretty similar in size so looking massive doesn't really swing it either way.
Edit - cross posted with Andrew.
Fair point Lou. Thought it might be the angle myself and was swayed by field observations of loud fast song and hovering. Difficult to make a call on the photo alone, but Joseph's confirmation of the song match sounds compelling.