Where I'm coming from is that the camera photos do not show the VRM, nor indeed any characters at all. In my view, the evidence has been tampered with.
As above, what you have is not necessarily the evidence they will intend to rely on to convict you.
They have no obligation to send you anything at this stage, other than the NIP and the request for driver's details. So imagine that's all you had. When you respond to that request you will have two choices. You will have to say that either:
1. You were the driver of that vehicle at that time and place or
2. You cannot identify the driver.
If you opt for (1) you may find it a little difficult to persuade the court that you cannot be guilty because the police cannot show it was your vehicle. Apart from anything else, they will have a statement from you confirming you were driving your vehicle at the time and place specified.
If you opt for (2) you will be prosecuted for failing to provide the driver's details (FtP) and the speeding matter becomes irrelevant. Defending the FtP charge may be a bit tricky because it
was your car and you were driving it at the time and place mentioned. Of course you could ignore the request entirely then the result will be the same.
The police have clearly identified your vehicle correctly. They haven't simply picked your name out of a hat. You need to accept that and move on.