Cats while being elegant and much loved can also be a darn nuisance kirkcubbin, I can understand your neighbour wanting to deter a cat highway.
Our home had been empty for over a year when we arrived and had become a communal cat toilet Leaving a spare window open at night we found evidence of cat presence in that room in the morning. Windows had to be closed. The first six months were spent removing more cat poo than I ever thought to see in my lifetime. Gradually many of the cats became tired of being chased away, friends visiting with their dog gave us a cat free zone for a few days. Bliss.
We don't dislike cats, we do dislike some of their frankly antisocial behaviour. I truly don’t understand why it is deemed OK for cats to use other peoples gardens as a toilet, dig up plants, dig holes in pots and generally cause a nuisance.
One day we realised there was no more excrement in the garden. A ginger cat was often seen chasing others away as he loved to sleep in the front shrubs and I assume didn’t want to be disturbed by others. We’ve never fed him but do put out clean water as he spends hours patrolling the front and side entrance to our home, never to our knowledge leaving a mess in what has become become ‘his’ territory. He is rarely seen in the back garden but does sit regally on the fence.
We’ve been here for eleven years now, ‘our’ cat is getting elderly, less energy to chase others away although he still tries. We still have no idea where he lives, he’s well fed, and worry that one day he’ll breathe his last in our garden and can only hope he’s chipped so his owners can know. As he gets slower we’ve noticed cat excrement is returning. So far judicious placement of prickly rose pruning is a deterrent in the borders, the garden is quite small, large tubs now have a chicken wire covering.
Your neighbour may not be the chattiest in the world kirkcubbin and you may never be the best of friends, I wouldn't say he’s nasty though. Discouraging a cat highway seems perfectly sensible to me, after all he might find clearing cat mess as unpleasant as we do.