Just a bit of an update.
SB recommended that I change over the homing sensor kit, so I bought one of those and it arrived yesterday. Today I drove down to the house and pulled the old one out and installed the new one. Which was a pretty easy job really. Took me a bit over an hour.
Turns out that the cable has been rubbing on the inside because I inadvertently cable tied a portion of it further down which in effect restricted the movement and caused the rubbing. That rubbing wore through the cable and severed it. Hence why it was not working.
Up shot is I know have my PME back in operation and homing as it should. Pretty happy with that.
