I’m pretty sure my car (neutered male) has started marking in the house, I can smell it but can’t find it, seems to be near his food gown and near the back door. Recently a neighbours young Tom has been coming into our garden which seems to have upset my cat, yesterday my cat tried to chase him out but came off worse. I have tried using the plug in thing to create a calmer environment indoors, my cat spends most of the day indoors but often goes out at night, I don’t want to keep him in as he’s ten years old and has always gone out. Is there anything else I can do to stop him marking in the house?