Coolant Temp Sensor - 2.0 TDi 170 engine

[Pedrödelabongo]

Can anyone tell me where this is please?
Tried Googling it, but still can't find it!
My engine:


Also, any idea what this brown wire is for? Doesn't look like a standard wire:

 

[SDHA4SLine]

About 4 to 6 inches down the back of the block, a pig to get too

 

[Pedrödelabongo]

Aah, that'll be why I can't see it then!
Cheers for that, will get a little mirror on a long handle down there……..