Ensleigh has been turned into flats. I'm not 100% sure if they were still in development or if they were inhabitated at the time this happened. So risk of people hearing him and coming out to investigate if they were living there but also literally beside Bev Road path and high chance of close proximity passers by too.
The part of ORPF he took her is close to the back of houses but they are not right beside it and also have back gardens so doors not instantly accessible. She would have had to go up the road (which is more like a track or tenfoot at that point and quite desolate looking) and round to the front to get to peoples doors or a well lit residential area - but she may not have known this. Although it's very close to her house, unless you were going to the park, or she had friends nearer that end she'd have no call to go there. It's more family homes than student houses.
One thing I often think is that if Libby did give him her address it would have played perfectly for him as it could look like he was driving her there and just missed the turning. Therefore not really alarming her too much until he got to Oak Road. If he had already planned to take his victim there she unwittingly played right into his hands.