I have three Zwartble X, and I can not get rid of them. I even baa at me when I litter pick the road when the can see me through the hedge and over the dyke.
I keep threatening them, but our dog can bark at them and they will sometimes chase the dog, the only thing them are really wary off is our welsh pony who will push them off the hay. I move them by following a bucket where I get mown over, its a bit like crowd surfing, with the dog barking at them which is no help at all.
They have mown the grass beautifully and my next task is to set up some more fencing so them work there way though my orchard over the winter. I just need to teach the dog to herd.