He's doing well in the polls someone pulls out an incident from over ten years ago to discredit him, why wasn't this bought up at the time ?..

Hi, Recently I received a letter from the local force with an accusation of me going through a red light at a pedestrian crossing. This letter was simply asking who was driving at the time. However, the very odd this about this letter was that it arrived within less than 32 hours of the supposed incident, 2nd class. Of course, I responded to say that I would have been driving at the time. I then didn't hear anything further for 6-8 weeks, until I got a call from an officer wanting to come to the house to discuss the incident. Having spoken to the officer, it turns out that he was the one who witnessed said offence while off duty but has a dash cam (he tells me I actually braked for a yellow light and then took my foot off and went through on yellow). Now, to me it seems very odd that an off duty police officer witnessing and reporting an incident would also be the one dealing with it. It very much feels like a conflict of interest and that he should be a witness only and that a different officer should progress it. I also find it odd that the supposed offence was reported and a "who was driving letter" appeared so quickly. To me this suggests that I did something other than go through a yellow light to upset the officer, I suspect using the second lane of a dual carriage way to go round him (perfectly legal to do) could be the reason. he came to the house to caution me and tell me that I should expect a court summons. Does anyone feel that this is a conflict of interest and that the police officer is acting alone with an emotional response to something I'd done? Is there anything I can do about it? Also, am I legally entitled to see the dashcam footage before pleading guilty/not guilty?