The Reid wrote
Does anything actually work at discouraging cats from using an area as
toilet? The product I tried had no effect (no need for shotgun type
suggestions, I don't hate cats).

I heard somewhere that thin plastic garden mesh laid over the area (and
presumably pegged at the corners), really puts them off because they
can't do their scraping and digging at all easily - they get tangled in
it I suppose.

Or would mouse traps deter them?
--
Roger Hunt