This seems too good to be true but found this with Google on eHow.
Looks like they are saying go to super lock for three seconds.
You need to get a FOB.
Without the FOB - you are really screwed and hosed.

No one survives on just a key man....
Actually, you should just find the lost FOBS.
Kids who lost them know where they are.


Instructions

1.  
   • 1 Stand outside of the Range Rover with all of the doors of the vehicle closed. On the integrated remote fob and key unit, hold down the "Lock" button continuously. While holding this button, place the key into the driver's side door lock.
     
     
   • 2 Continue to keep the "Lock" button of the fob held down. Rotate the key clockwise in the door lock. Keep the key rotated as far as it will turn for three seconds. Rotate the key back to the center and remove it from the lock. Do not release the "Lock" button.
     
     
   • 3 Stop holding the "Lock" button on the fob once the key is completely clear of the door. The fob and the Range Rover will synchronize. The remote buttons will now control the locking functions of the vehicle.
     
     

 

On the advice of a co-worker, I called a reputable LR dealer in the lower 48 and asked the service guy if I really need a fob to re-mobilize my Disco (good idea). The service guy said, "Yes and you have the second problem to address - why did it immobilize?" Also, he said I will need to bring the vehicle in to the dealership in order to program the new fob to it - not an option.

My plan, then, will be to, 1) see if the previous owner's kids found the fob and, failing that, 2) buy a new fob and try the ehow procedure, and if that fails, 3) haul it in to the local garage and buy the programming service done.

I've looked at the battery connections and fuses again = nothing amiss that I can find. I determined that I don't have the ultrasonic interior protection option that could have caused such a problem. I don't know if I used the cell phone in the vehicle - the owner's manual says don't do it as the interference may cause problems - so I don't know if a phone may have caused the problem. Still at a loss as to what caused it.

 

It should disarm with the key. Either all by itself, or with the EKA. I've done it on my 99 a couple of times. It does take time for the ECM, BCU, and IDM to all start talking to each other. When I disconnect the battery for very long, after hooking it back up it might take 10 minutes or more for the alarm light to behave properly... then if I unlock the door with the key, the light should go out, and it will start.

 

Please educate and tell us the proper behaviour of the alarm light.
I have never understood this.

 

The LED has a dedicated signal from the BCU to indicate the status of the following:
Alarm armed: The LED flashes at 10 Hz with a 50:50 duty cycle for 10 seconds, after which the LED flashes 50 ms on, 2 seconds off until the state of the system changes.
Engine immobilised: If the engine is immobilised and the ignition is on, the LED is illuminated continuously. If the engine is immobilised and the ignition is off, the LED flashes 50 ms on, 2 seconds off.
Alarm tampered: If the alarm has been triggered, the LED flashes at 10 Hz with a 50:50 duty cycle.
Handset battery low indicator: If the handset battery is low, the driver's door is open and the ignition is switched off, the LED flashes two pulses of 50 ms on, 50 ms off, every 10 seconds.

 

I need to print this and put it in the glove box.
Too much to remember.

 

Yeah. The only part I remember is that if you see the light... at all... it's probably not going to start.