Update: Went in for the 2nd time just before Christmas. Dab radio fitted foc as it was advertised as having it and it didn't = cool. PID replaced after technician came for a drive with me and witnessed the issues. Still having problems with the stereo jumping randomly to aux and media from the radio and now the radio reception is utterly useless. Awaiting callback for a third attempt to sort it but I've already mentioned rejecting the car to Skoda UK and it might have to come to that. Annoyed is not the bloody word.

Having trouble with navigon 70 pid reading car trip / info it's been updated now won't connect to car with ignition on any ideas

Seem to have solved the random switching between sources by doing a factory reset on the pid and switching off auto connect and auto play in the phone menu. Been ok for a few days now touch wood. Now to get the radio reception sorted.