What to do about awful mess in garden created by neighbours?

[judethepude]

Some years ago, a previous neighbour built a dreadful breeze-block wall above my lovely dry stone wall when he selfishly raised his garden by several feet without any consultation with us. He also poured tons of concrete everywhere, which is incredibly ugly. I was ill at the time and left it too late to take any action. New neighbours moved in, and made the situation worse by erecting a very tall wooden fence another few feet above the wall. None of the structures is on my property, (except for some horrible modern stone 'buttresses' that the first neighbour sent the builders round to construct without even consulting us). but I now feel as though I'm living in a fortress. It's horrible, and the dry stone walls were one of the reasons I originally bought the house! Is there ANYTHING I can LEGALLY do?? A trellis has not made much difference. I am definitely going to pickaxe the buttresses into oblivion this summer.