DC --
Am sorry to hear what happened to you..
Am totally on board with what AddysDaddy -- do not acknowledge the dog, no eye contact, no talking to it, etc..
You also have to come in to that situation totally confident, not scared, no fear deep inside, you are the boss. You are not there to boss the dog, but you are the boss of your part there, and the dog if its not crazy, will acknowledge this in time.
I cant believe they would let it bark all day while you were working outside.
I have 2 purebred AKC registered German Shepherds, 1 East German, 1 West German, and they are also very protective of our house and inhabitants, and they will bark at strangers, especially if they are in the house, so I have to tell them either through a visual motion or vocally that it is ok, no barking, these people are "on the list", and then the dogs will "release" from barking.
Perhaps this dog owner needs to spend time working on this through the inside of his house, with the dog inside, and the dog will get it (hopefully).
I think its very rude and thoughtless of any owner to allow their dog/s to bark, etc., at strangers like when you are walking down the street and they are walking their dog.
I personally feel that the dogs that bark are not sure of themselves, do not get enought exercise, and maybe have become a little crazy from never being outside and getting exercised and disciplined. All dogs need a job - every day. If they have that they are way better off and so are the owners and people who come across them while they are on a leash.
My dogs see other dogs bark at them all the time when I am walking them and they just ignore them, cause they know they could eat that little barking furball in 1-2 bites..
Perhaps suggest nicely to you Client that or ask if that dog has ever been to a school.. ?
You can usually tell by looking at a dogs body language what it is about to do, so the owner of this menace-in-training needs to also be trained in how to look for these tips.. But the absolute best thing for any dog is to get trained properly, and if its a big, strong, dog, you have to have a pinch collar on it when you walk it, otherwise, you may not be able to get its attention when you absolutely have to..
Good luck with this, sorry it had to happen to you..
Dan F