Ellisr I've read your various posts over the months and you seem to have such problems living there. Of course I don't know both sides of the stories but just from reading what you write, I think it is time for you to seriously consider moving. You get so much hassle from so many different people.
All the moving problems and grief of finding another place aside, there
are other properties out there with a bit of land. What you go through from those around you at that property is not worth all the worry.
Re the dog, it shouldn't be in there, end of. I would ring the police if it entered again and report it for sheep worrying - and when you see them next tell the dog owners that is exactly what you will do (so they know in advance, it might make them think twice about allowing it to roam). Say it in a 'nice' way, but stand your ground.