Never, never, ever, involve yourself in legal proceedings solely because you feel you have been wronged. You should only challenge the penalty if you receive independent professional advice that you have a strong case. As I have said already, and as others have said, if it comes down to your word against the word of two police officers, the magistrates will believe the officers. Look at this way, the courts are full of people protesting their innocence, but in the great majority of cases they're not innocent so why would the magistrates believe you? You know you're honest and that you've been shafted but the question is - could you convince them in the face of two officers who will swear that they saw you put your belt on at the last minute. The cost, hassle and stress of going to court will only make things worse if you don't get the outcome you want.