Car is 2008 Audi A3 1.9TDie

I hv had warm start issues sometimes lazy, but today just wouldn't start.
I have found what I think is the G83 'grey' 2 pin sensor- just by dipstick behind radiator car started straight away- no sure if this is a coincidence as car had cooled down.

I just cant find the other G63 'green' 4 pin sensor.
Any ideas please, pics would be appreciate

thanks in advance