I was informed by the Police on making an enquiry, that
"Although the footage shows a driver with a phone in their hand, this does not prove the offence, when considering bringing a charge against anyone, we have to ensure they can prove the offence. In the case of the mobile phone legislation, it states that not only do they have to be holding a hand held device but we must also prove that a telecommunication also occurred, such as a telephone call, text, using maps etc. If a telecommunication cannot be proved then the legislation signposts to other offences.
As I am sure you can appreciate Dashcam footage can show a phone in someone’s hand but the majority of the time it does not show if a telecommunication has been committed, in these cases we will look to see if other offences can be brought and when the evidence is there we will continue with a prosecution for ‘Driving without Due Care and attention’, ‘not in proper control’ or ‘careless driving’ etc, which can have the same potential sanctions as the mobile phone offence.
What I can assure you, is that we have prosecuted some drivers for ‘using a handheld mobile phone/device whilst driving’ when we have the evidence to support this. There has been a recent case heard in the High Court, that is now case law, which supports the Constabulary’s stance which you may be interested in reading DPP v Barreto."
Now, that case is interesting and I can see that the Police's approach is correct (albeit presuming that the driver will allege that no telecommunication was taking place).
Therefore we must hope for a change in the legislation. I was told that if a helmet camera report of mobile phone use wasn't sufficiently clear to support prosecution under the mobile phone laws, and in the absence of other offences such as careless driving, the registered keeper is sent a warning/advisory letter.