OK now I've calmed down a bit... got the NIP thru last Sept saying I did 65 in a 40. I wrote back saying that yes, I was the driver.
The NIP told me where it was, and it was on the A40 on the way to work where they had just installed a new camera near some traffic lights. I saw the camera, and, as there were no marker lines on the road, I thought it was for snapping drivers jumping the lights. BUT it must have been a speed camera, cos I got the NIP for speeding.
So I wrote off asking for photographic evidence, knowing that their photo would not have any marker lines on the road cos theer weren't any. True the radar will have got my speed, but with no image of my car passing over the marker lines, I reckoned they would struggle with the case if I contested it.
And it looks like it worked! I'm well chuffed me!