I have a very strange problem with my Pure Oasis Flow radio. When receiving digital radio, the clock time shown on the display is always accurate. If I turn off the radio, the correct time is displayed for about 30 minutes then the clock time loses about 7 or 8 minutes and remains 7 or 8 minutes slow until I re-start the radio and tune to a digital station, whereupon it corrects itself. The radio does not correct itself with any internet station, only digital. If I do a manual time setting the same thing happens, although the period before it loses the 7 or 8 minutes is usually shorter. I have tried resetting (removing the battery connection and starting on the mains adapter only), and also done a factory reset (as per the instruction manual), but without improvement. Anyone any idea how to fix this ?