Scantronic 9751 RF Failure Back Door?

I changed the battery on the contacts at both the front and back door, zone 1 and zone 7 as I was getting a battery failure alarm. I am now getting a RF Failure on 215/back door. The amber light is on but I do not know how to reset it to clear the alarm, is is it still faulty as it claims. i moved the connector near to the alarm panel to see if it would reset due to proximity but no joy.