Jack, a working dog who's recently moved to the city, barks continuously at the postman on his rounds.

I'm not surprised that Jack wanted to "have" the postman. First of all, he was a working dog and the sound and movement of the bike would be a strong stimulus. Secondly, the dog was merely protecting its territory from what it considered to be a threat - the postman.

Initially I needed to find out if it was the bike or the person that caused the trouble. In fact, it was a combination of them both that really set Jack off. The only sure-fire way to control this was aversion therapy.

We had to make the postie something to be avoided, because confrontation with him would prove to be unpleasant. Using a "Spray Commander" (A.B.S) which attached to Jack's collar, we could deliver by remote control:

c) A long burst of citronella

It worked like a charm. By the time the postie came back for his second pass, Jack was disappearing down the back of the property with the scent of citronella! Score "1" for Australia Post & the owner!