Hi Lowie
Colin beat me to it, Horizon is the UK distrbutor for Spektrum they can fix the problem.
The offical statement:
Spektrum DX3R Product Bulletin
Horizon takes your satisfaction very seriously. While thousands of DX3Rs are in use with excellent results, it has come to our attention that a few DX3R transmitters are randomly “losing bind." After significant Investigation we have determined that for a small number of radios purchased when this system was first released, there is a possibility that bind information can be deleted when switching models within the transmitter (from say model one to model two) or during power up. Again, this issue is isolated to a small number of early radios. These radios carry ID codes ending in 0712, 0801, 0802.
A quick fix is to simply re-bind the receiver. Be assured that the issue will not, and cannot, affect your RF link during operation. If you are experiencing the “losing bind” with a radio that has one of these three codes and would like to have it repaired, please contact: