Yes the rears have the reluctor ring around the end of the bearing face, the sensor is in line with the drive shafts pointing in towards the bearing edge. Anyhow, all four reluctor rings test out perfect with all of them not missing any pulses. The front have a more conventional ring with serrations in. I am looking at the rear discs now, which I am hoping will cure the fault. I have fitted new discs on the front a couple of weeks ago ready for the upcoming MOT.
The little hand held scope is a fantastic bit of kit for the money and worth having for the 20 quid it cost me.
Sundance