From memory you use the button bottom right hand side (just out of shot on the photo) to turn to time required then push to set. You have to do this for the date, hour and minute.
I know it doesn't answer your question, but shouldn't the clock take its time from GPS? There's even a satellite icon on the display, which to me sort of implies it's involved somehow.
hi,
managed to change the time using the buttons as suggested, so the time shown on the screen is correct - however the digital display on the dashboard above still shows the incorrect time.