I mean we have traffic cams here but they don't write tickets to other officers... Lol.. matter of fact my state outlawed them. Because the companies that were installing/ monitoring were not using sworn officers to send the citations and weren't even in this state
My understanding on it, is it's all automatically linked, so it's unbiased between Emergency services and the public. Plus the way vehicle registration and insurance works here is quite different to the US, so the ticket goes to the registered owner/address regardless of whether or not they were driving at the time. (We have quite a "duplicate plate" criminality element here, where crooks will find an identical vehicle to one they've stolen, and steal the plates, so without checking the VIN it appears legitimate.)
Oh that's a point too, unlike in the US, where you can lend your buddy a vehicle, in the UK if you intend to drive someone else's vehicle, you either need to be named on the vehicle or have your own fully comp third party insurance.
With regards to the Police getting caught by the cameras,I believe the support staff can trace the Officers driving, and check if they were actually on a call or not.