Watching for ideas....
My NDN dog is a noisy (smallish) one too.
Today , over 2 hours (I can usually filter it out, but I'm a bit grim today so it hacked me off )
Often (like today) there's nobody in, but I really want to hammer on the door and ask them to get the dog to STFU entertain him (like take him out would be good 
You'd think two dogs would be company but of course they bark double.
Unfortunately, 99% of dogs do bark at times, some more than others
I think when dog owners live with the noise, they kind of blott it out?
It is annoying though. Can you mention it to them, the 5am and 1am wake up?
Like "Oh was there something going on outside - fox/burglar/random person in garden- because your dogs were barking"
If they say "Oh yes something set them off" then fair do.
If they do the Tinkly Little Laugh and say "Oh no, they always go off on one" then you can scowl and say "So it seems. Can you sort it"
They might sleep through it?
(In which case wait till theyre home late one night, hungover, and keep waking the dogs up, walk past the house, knock on the walls)
I'm plotting.