Ooh missus! Nisus accipiter!
Great picture, mate. I believe it is neither a Swainson's nor an osprey...
I also believe it's not that old. Guessing from proportions and colouring, it is an older juvenile that has lost the fringes to its mantle feathers, and it may actually be a male juvenile from the proportions. Head and feet look a bit lightweight. Mantle colour /breast colour are female, but juveniles are that colour as well (just scaley). Will have a closer look when home.