
Queer as it sounds Sharon (fellow Bristolian :D) because my Lexi reacts to them, I actually end up taking the dogs out into the din, as I have found they don't react to them while I am out. This seems to have helped her settle when they are goining off when at home (this being her first real bonfire night (she was 8 weeks last year).
So if your dog is not reacting out of fear, but more due to defending home from unknown invaders, actually taking them otu to see what they are can help. Of course I would only advise this if you are absolutely sure they aren't afraid.