What is this plug in front of my radiator 05 D3 TDV6 HSE?

[Nankas]

https://www.aulro.com/afvb/images/imported/2018/01/974.jpg

[LRD414]

Looks like the unused plug that normally sits into a blanking socket, seen here with orange pin blanks.
I understand it's for a pollution sensor not fitted to Aus vehicles.
Ignore the light grey plug, which is my driving lights wiring.

https://www.aulro.com/afvb/images/imported/2018/01/979.jpg (https://flic.kr/p/22fKusG)

Scott

[Nankas]

Cheers Scott, my car I think was one of the first in the country and was built to English spec SALLAAA135A000453 Built June 04. No rear air in the HSE. I have the deisel pre heater under the bonnet. Maybe I had the pollen sensor subsequently removed and not blanked.

[Nankas]

Correction should have read fuel burning heater not pre heater.