Homer is right - cats are territorial animals and use urine as a means of marking territory borders. Youmay have to accept that your cat is marking its own area, and live with it. Speaking as a cat-lover, but without cats, the local cats find my gravel irrisistable, and three or four of them compete with faeces to claim it as their own. If I thought my neighbours were discouraging their pets' use of their own garden as a toilet, I would not be impressed - dealing with by-products is the downside of owning a pet, and it shouldn't be foisted onto your neighbours.