I joined this forum just to answer the question as the last person in the thread hadn't spilled the beans and I understand just how frustrating this problem is after sitting in my car with a torch late at night. Loads on the internet about this if yo Google it.
Anyway, the answer is very straightforward. Just press the FM 1/2 button and the large 'TP' display symbol should change to 'FM 1'. This is like the picture above.
This is not to be confused with the smaller TP symbol on the display (just above in the picture). This is always present when the transport programme signal is being received.