What is the difference between the primary and general images from a speed camera?

Posted by acrowandababy@reddit | AskUK | View on Reddit | 3 comments

I've just got a speeding notice saying I was going 43 in a 30. There are two evidence photos. The 'primary' shows 43, but the 'general' shows 42. Is there anything I can do to appeal the decision to claim I was going at 43? The 1mph is the difference between points and a fine and a drivers Ed course.