The last 2 that we had this problem did not have flat batteries, ( although I have seen dozens that did suffer with flat battery problems ) I put the immobiliser fault solely down to the stray signals from the phone masts.

I have also tested several for battery drains and found that they wake up when various non landrover remotes are operated within the area of the vehicle.

I will definitely recommend new ariels to the next ones suffering with this problem. ( Although I did on the last one and he thought it was easier to keep it away from the phone mast, but after paying for several recovery trucks, it would have been a lot cheaper to replace the ariel )

Tony.