Free Traffic Legal Advice

Hi, I wonder whether anyone can help me

I received a NOIP from the Metropolitan Police for driving, on the M25, 79mph in a 70mph zone (I contest this as I truly believe that I was not going that fast. At most a few mph over). Anyway I found a piece on the Metropolitan Police website (following a Freedom Of Information (FOI) request) stating that the Met Police cameras operate with a tolerance of 10% + 2mph (https://www.met.police.uk/foi-ai/metropolitan-police/disclosure-2023/march-2023/fixed-speed-cameras/)

As a request I responded to the NOIP stating that if the Met Police state as a fact that their cameras activate with a 10% +2mph tolerance, then as I am on the outer limit of the tolerance why did it activate i.e. the camera should have triggered for speeds greater than the tolerance, in other words greater than 79mph. I received a confusing (non-sensical to me) response citing amongst others "...The MPS changed the enforcement threshold from 10% +3 to 10% +2 for offences with effect from 14 May 2019 which was after information that had been previously published....." It did not address the central tenet of my argument in that why did the camera activate at 79mph because accordning to my maths 79mph is exactly on the tolerance limit.

I truly believe this was a faulty camera, but I cannot prove it. So I would really like to challenge this NOIP based on the factual information cited in their FOI request.

I have attached the following

1) The original NOIP   
https://1drv.ms/b/c/a4fab795b7ba1645/EZc90WPyr8pEgdaUm0N-OZABrhD15ZQGgTJapd80ylOpOg?e=aRxaAm

2) The response letter i wrote:
https://1drv.ms/b/c/a4fab795b7ba1645/EcQXgmAA4HBDj-OGzvfO2PUBGBzjjH4qbjnsGPbKnuKKhw?e=oIgdJE

3) The MET police response to my letter
https://1drv.ms/f/c/a4fab795b7ba1645/Enq4X9CAun9JkN7LwosBqDUB739sR0h1oAI61IMkO1DfsQ?e=GoaeGg

Any guidance will be greatly appreciated