[PennysMum]

I'd probably add a sign on your gate near the latch-- one of those BEWARE OF DOG signs would work, just so that anybody who goes to enter the yard is aware of the dog and doesn't enter the yard unless they know where the dog is.

One of my neighbors when I was a small kid nearly lost their German Shepherd when the gas meter guy entered the yard while the dog was out there with the family's little boy. Their dog wasn't aggressive, but when someone was trespassing near her kid, she backed the meter guy into a corner and nearly bit him. There was a big fuss over it, but thankfully the animal control officers in our town sided with my neighbors in saying that she was only being the protection dog that she was born to be, and the gas guy should have been more careful. They put up one of those signs on their fence though, and from then on the meter guys would knock and ask them to take the dog out of the yard before they went back there.