... and I'm starting to think he's right. DCat will not stop pooing on his lawn (middle of grass, won't bury it). Have tried two types of sensor, one worked well for a while but then got less effective.
Have also tried digging loose earth in my garden, introducing him to it, scattering his litter (clean and soiled) on it.
I have tried so hard not to let him out until he poos in the litter tray, then let him out immediately so he associates the two things in his mind (tho is he even capable of that?!). But often he just does it anyway.
At the end of my tether, and neighbour getting annoyed, saying he'll just have to be an indoor cat. What other option do I have? Please help!