Thank you for the hint.
Removed the rear passenger side wheel and found the sensor wire was almost worn through .
Wire was dislodged from the holding bracket and was hanging loose and rubbing against the rotor.

What have I learnt?
When getting a similar warning appearing on the console, check the electrics before presuming the fault is mechanical.

I now have a new front & rear set of pads ready for use.

Sorry guys, I am rather embarrassed.