Flash question

Hi together, as already written I fell yesterday at a building site to a blitzer for sacrifice, whereby I can not explain why this happened at all, because I had 55 on the tacho and had to have been allowed 50. the problem is the following : the building site exists a little longer, until about two weeks ago there was still a sign which pointed to the tempo 30 but now is not there anymore. I can’t imagine that the blitzer sch on at 5 km/h too much triggers, so now I have a bit shot that was set to pace 30, the question is what I can do now to prove that there is definitely not a 30 sign. simply with a video camera the track movies? (no new 30 sign has been built up so far) how long should it take to get mail with a photo of me? I think it will be a bit difficult to prove that the 30 sign at the time of flashing ni cht was more there (that would be in case it would be rebuilt soon after all) how would you behave ? I am grateful for every council to clarify beforehand how much was now allowed at the site.