I can only go on what i would do. If i heard a barking dog that wasn't barking before, it wouldn't be a problem, unless it was weeks on end. (he said the bf was there the first 2 days, so its been 3 days at the most she's been away)
Council have laws regarding such things (which i'd assume are completely different if you dont live in metro)
A bark every now wouldn't piss someone off to the point of putting a note on your door...
I dont see the difficulty in putting your pet in a kennel if you aren't able to look after it which results in it disturbing your neighbours.
My sister inlaw has two dogs, the dog behind sets them off on occasion, the people next door bitch everyday that they're being noisy and barking, also very well looked after spoilt dogs, sad part is, the ones complaining about the barking have two dogs that do most of the barking,
It may not even be this dog or dogs in question, good chance it is, but possibly not. I agree with the busy bodies, especially after 3 days.
If it was at night, fair enough, but the op would have done something about that stopping him sleeping, this tells me it's during daytime, which tells me it's one of two kinds of people,
1 retired old codgers with nothing better to do,
Or
2 dole bludgers wanting to feel important.
You can't complain during the day.
Taking donations of cash, card or full frontal nudity.