HOW TO COMMISSION A DRAYTON RF2?

Our drayton rf2 is not working any more. I have downloaded the instructions and gone through the re-commissioning procedure, but it still doesn't work. When I press the 2 buttons to go into learn mode, the red light flashes, I then remove my fingers and the green and red lights are supposed to be lit, however only the red one is. I then replace the battereries (right ones first) and it still doesn't work. Can you please help?