Interesting hypothesis about PS. I remember PS saying, in defence of CJ, that GR had not mentioned going to Sheffield while they were starting his car. But did he say that really to protect himself - as if to say if CJ didn't know about Sheffield, he also wouldn't have known - whereas actually he could have known by, for example, overhearing GR on the phone to Sheffield: "Hi, just leaving, see you in 3 hours....".
He may also have "innocently" spent some time on the scaffolding overlooking their flat in the weeks before the murder, during which time an unhealthy interest in its new, attractive female occupant was kindled.
But I'm not sure about the ease of removing of the body. I think he'd have had to take it up the path, through the gate, and round through his own gate, ie about the same amount of effort as carrying it to a car parked in the road. I don't think he threw it over the fence!
