As far as the UK is concerned, you can log the hours as P1, providing you are within the 90 day rule for carrying pasengers and the instructor agrees that you are P1, doesn't log the hours and its your name in the tech log. If the instructor logs the hours and its their name in the tech log then its dual, as stated above PICUS can only be logged on a successful flight test.
Hope that clears things up,
regards,
Han.