mat - live, common and earth
supply - live common and earth
probe - brown, white
Probe resistance is in excess of 17 Kohms
Unfortunately the probe is burried in the tile cement and not in a tube and hence it canot be replaced as easily as it should be.
I was thinking of replacing the thermostat and sensor for £25 off of ebay and just tape the sensor to the floor to run a test and if that fixes the problem then I may have to take up a tile to replace the sensor.
I assume you answer means 'by-pass the thermostat