If it was that easy, everyone would do it.
In the absence of any concrete lack of certification with the equipment, and even in the face of blatant failing to follow the ACPO guidelines you will generally get found guilty and the penalty would be double and you would also have to pay prosecution costs.
You ask whether it’s worth it for them. The CPS and the police don’t think of this in terms of money. If you go to court and have a fully contested trial, it will cost more, far more than the penalty.
You can ask for all the video footage and all the officer records and they may let you have them or not. Sometimes they do, sometimes they just say that you will be able to view the video on the day.
You can ask for a copy of the video footage under the Data Protection Act section 7 by making a Subject Access Request and paying the standard fee of £10. They have 40 days to reply. They can argue that it’s legally privileged for use in court proceedings and that they don’t have to produce it.
I’m going to be very honest with you and tell you that one in 10, if that, of these technical/loophole defences succeed.
Each time a loophole has been discovered, it is closed in a short time afterwards.
Whether you go to the trouble of defending this or not depends on how valuable your time is, to go to court, which will be a day and whether having the points on your licence makes a big difference.