Hi,
A very technical point is that a "phone" is classed as " a device capable of making or receiving a a phone call".
So touching your smartphone to use the free SatNav software on it actually is touching a phone while driving. Touching is using. That is breaking the law...
The police officer will doubtless listen to your explanation that you were not phoning but could do you...
Robert. ( ex Magistrate, got too busy at work).