The first thing you should do is that you go the the civile compliance office to aske them show you what was your detected speed.
If your car was made before 2006. Then, you can make the lawful claim or excuse that you were not overspeeding because you can consider the legitimate tolerance of the detected speed.
The legitimated tolerance of detected speed on the speedo of your car is 10% of the real reading. and the tolerance on the camera is about 2kph or 3kph.
If your car was made after 2006, you still have legal ground to fight the case. It becomes more complicated fighting.
I did not type in Chinese because my pc does not have chinese typing soft ware. If you want to know more tips you can call me on 0401283022.