So many questions...
The law on use of radios etc is very strange
I cannot hold my mobile phone...
I can hold the mic of my ham radio
The police (and the other services) are exempt for radio use, as are taxi drivers, and ham radio operators.
If I were to have an accident whilst holding the mic of my ham radio, it would count against me, as it would the police officer etc, but to actually hold it is not an offence.
Strangely, if you were talking on a hands free mobile phone and had an accident, and it became apparent you were using the phone, I'm advised you would be deemed to not be in proper control of the car.
Its a complete mess, and this is what happens when the government tries to spin safety.
As for smoking in the car whilst driving.....get lost lol, but that is a personal opinion !!