People are not awful - they are entitled to an opinion. Keeping dogs without social contact from 8-4 will result in them barking at anything.
Including (in our next door neighbour's case) people nearby, people putting washing/bins out in their own garden, cats, birds, squirrels, a van reversing, someone sawing, anything they can see or hear that is out of the ordinary. It is all very well saying they are quiet when you are there, but obviously the neighbours have reached the end of their tether in the daytime when you are not there.
Legally, you can do nothing other than apologise for the noise, and try to put things in place where your noise is not inconveniencing others.
If there is a noise abatement notice given, then you have to find ways to stop it, perhaps try thinking of how to stop it getting that far.
(a long walk before you go to work, a dog walker taking them out at lunchtime - no access to the garden when no-one is in - your house insurance would be invalidated in any case if you left a door open every day!)