I hadn't realised, from the other end, that this little alley was part of the churchyard rather than a way through into a private back garden; it looked as though it might pop up in the Bishop's House, and you don't want to disturb a bishop. When I worked out it just led through to the main church area I decided to walk it just for completeness, looping around and out through the memorial garden again.
GPS Coordinates:
51.45364, -2.61422
Location: Cliftonwood