thanks Andy
I thought about it last night,

The new sensor is a genuine one, i had to modify it to make it fit,??

Altho there is a fog light present and still an extra wire near it and the spoiler is missing about a 6"x 8" piece of undershield where you would expect the ambient sensor and also the clip retainer is missing from what looks like the ambient sensor plug. And also the problem occored when this part was broken.
Could this all be a coincedence???

I looked again all around the inside of the grill and spoiler, then i found it!! It is moulded into the undershield below the fog light on the near side. I traced back the wires and found a broken wire. Fixed this and all is good!!

I was looking past where it was expecting it to be internal on the inner spoiler/grill not actually external undernieth the spoiler.