Further information on using satnav screen whilst driving.
'Failure to have proper control of vehicle or full view of the road and traffic ahead, or using a hand-held mobile phone while driving (CU80)'
Section 41D Road Traffic act 1988.
Whilst this IS primarily used for drivers using mobile phones etc, whilst driving, it can also be applied to any situation where you remove a hand from the steering wheel, except to change gear or operate a control system in the vehicle (window, de-mister, etc) provided that your control of the vehicle is not affected.
IF you are having a ***, eating/drinking, operating the radio/CD, twiddling the satnav or doing anything where your attention and actions detract from your 'proper control' of the vehicle then you can, depending on the individual circumstances at the time i.e danger caused, be summonsed or given an FPN (E) for this offence.
It is often solely dependant on the interpretation of what has occurred, by the officer involved, as to whether this section is applied instead of a more serious or defined offence.
Either way you stand to go through a period of angst whilst you await a court appearance, or the FPN is processed and your driving licence returned with the requisite points attached plus you have to pay the fine and then ASAP inform your insurance company that you have been prosecuted, with the associated rise in premium for the next 5 years.