Hi again Dee!
As I think I asked earlier - have you been next door and spoken to your neighbours about it? Explained the situation and what you're trying to achieve? We're in the same situation (house-wise) and it really helped us.
What also happened (when we were out) is that they also let us know when Harry
stopped whining/barking, which actually put our minds at rest, as we presumed and worried that it was happening
all the time. It really might be worth a chat! Sally + Harry x