Dear angie and alf- my heart bleeds for you.
I have neighbours who just should not have a dog, poor thing left on it's own all day every day. maybe an outing at the weekend in the back of a truck.
Worst time is in evening, when next door has not returned, or if they come home and then go out again. Dog becomes menace.
I have 99% cured it by attracting it to the fence when it starts barking and throwing a bucket of water over it. The dog I mean, not the neighbour, who would probably gain much from the same treatment.. No, not cruel, as I have yet to wet the dog, she is very nimble and avoids the water admirably. But, I warn her, the dog, to stop barking, and now I only have to show her the bucket and silence reigns supreme. The dog and I are very good friends, and daily we play 'fetch it,' over the garden fence, but when I tell her to stop barking, one showing of the bucket and all is well.
I am a dog lover. by the way.
Good luck.