Hi Shaun

'You gave advice on identifying heater wires, to the best of my recollection they are all the same size, on the sensor they certainly are, it is in my hand now,
Thats why I said to check the wiring on the car loom side of the 02 multi-plug, you'll see what I mean.

'What I will need to do is get the car jacked up (I don't have a ramp as for 99% of my jobs they are a liability) Put some long test leads on the heater connector and continuity test back to the PCM and supply point, it would just be nice to know where they are.'
No need, jack the car up,removed the small cover and put an amps clamp over one of the heater wires underneath with the car running. No amps flow then dissconnect the 02 plug and check for a heater circuit power supply, again running. Perm power supply and controlled earth when running.
15 mins tops.

Hth Sean