Google says this feather is a from a great horned owl or an osprey. I don't believe it.

Can you give an idea of the environment that this was found in?
and if you have some time on your hands
www.featherbase.info/.../

I think you are right to discount the Great Horned Owl unless someone close by flys one

It's a perfect owl location and we have the odd buzzard and kite. Next to springs and untouched woodland. There's definitely noises at night.

Neighbours have peacocks and vagrant bunnies, unusual hens and there are pheasants everywhere when the farmers not about. There's some seaside meadows as well.

I'd say it's a hen but really not sure.