Out if ideas for stopping cats pooing all over my garden! Help!

I didn't know about this thread or I would have looked for advice on it. Some people have asked me for advice but cats are very persistent animals & will often frequent the same place time after time & it's difficult to know what to do with them. One thing I've suggested is prickly branches, rose or bramble for example.

This has only become (a minor) problem for me since I dug up & replanted with Daffs a very narrow border at the base of a wall & delimitated by a footpath on the other side at the side of the church I go to. In the loose soil the cats starting doing their "business". It's been worse at one end where there weren't enough bulbs, or later plants, because the soil is too shallow & there is cement from the wall & path. I suspect it is one cat as they are territorial.