actually, annoying as it is - dogs are allowed out to bark but not for longer than 5mins (or so) and not before 9am or after 9pm before it is considered a nuisance its not considered abuse for dogs to be kept outside and the barking has to be monitored every day in order to make an official complaint. You need to let the neighbour know. I've yelled out of my window to my two dog barker neighbours who have replied with "well, he likes barking" and have told her that we don't want to hear it. Perhaps a little embarrassment but they are a little better now. Hopefully your neightbour will respond positively, otherwise I'm afraid there is not much you can do apart from log it and report to authorities