Apparently, the same rules apply whether phone or sat nav i.e. you cannot touch it:
http://www.mirror.co.uk/lifestyle/mo...caught-9931996
Can you use your phone as a sat nav?
Yes – as long as you programme it before you start the car and set off and it's in a holder out of the 45-degree angle of the driver's view. You cant re-programme or touch it while in motion, the same rules apply for any sat nav.