She's about a year old and is an indoor cat due to her being half ragdoll, we were told they were not to go outside. We used to have a doormat on the inside but have taken it (and subsequent replacements) away until we fix this as she keeps peeing on them and they're hard to get absolutely clean.
She has 1 hooded litter tray in a quiet, private place. I have given her 2 trays before which she used but it didn't change the unwanted behaviour so I took the second one away.
I'm pretty sure there is a cat taunting her from the other side as I see it stalking around and I think i've heard her 'talking' to it through the door (then peeing there). I have put some of her poo outside the front door and tin foil both sides (neighbours must think i'm nuts!) hoping to deter both cats but she will happily pee on the tin foil. I clean it with urine off (have a black light on its way through the post to check i'm completely eliminating the urine), have used a feliway diffuser in the past (no difference) and occasionally use the feliway spray once i've cleaned the area but tbh I think that makes her pee there quicker!
I am running out of ideas. Please help!