Could be a Raven?

A large bird was patrolling the branches of a goat willow tree outside our bedroom window this morning, trying to find a safe way down.  It even called its mate to stand guard - and this is it, guarding from near the top of the tree.

They were both quite shaggy and had very large thick beaks so I think they might have been Ravens.  A pair was introduced about a mile away from here a few years ago, and they have successfully bred.  They have been spotted (not by me) on nearby fens.

I got several minutes of video of them which I shall show to one of our friends when he comes back from his latest birding trip to the Gambia.  He should be able to give me a definitive ID, I hope.

If they weren't Ravens (they sounded as if they were) then they were huge Carrion Crows.