Help Discovery Immobiliser Problem. Vehicle Dead!

Hi I just happen to have moved home so things have been slightly chaotic to say the least.
Just to add to my trials and tribulations my N reg Defender 90 County Station Wagon has decided to play dead.
I had it parked up on my drive and hadnt used it for a few days. When I went to it the fob didnt appear to be working to knock the alarm off.
I take it the fob battery must have been dead not that it gave me any warning that it was dying.
I unlocked the door and sure enough the alarm activated and obviously wouldnt allow me to start the vehicle. It just kept making a clicking noise from under the bonnet on a regular basis.
I have tried to locate the Emergency Access Key Code in the log book to no avail. There are two codes on metal tags attached to the fob one stamped RO followed by four numbers (which I take to be the radio code?) and one stamped E followed by four numbers (which I had hoped was E for emergency) But that code didnt appear to work.
Unfortunately my vehicles battery now appears to be drained due I take it to the clicking noise.
Anyone had a similar problem. Any tips greatfully received.

I am pretty sure it immobilises the earth to the starter relay and the supply to the fuel cut off. If you re wire arou d those 2 and. Barge the battery it should start. I am not sure how serviceable the alarm spider is. It is located behind the dash display so you could check for damp as water could be coming through the bulkhead somewhere

Thanks for the reply. Electrics are definitely not my thing looks so like I will be seeking assistance and reducing the cash in my wallet. Its a nightmare as I live in the middle of nowhere. Dont think it will be damp as the bulkhead and the rest of the vehicle are in A1 condition.

Sounds likely that a flat battery on the vehicle was the fault from the start.

Just a note... my Disco 2 just simply shut down and reset everything. I couldnt put radio code in, the clock had reset to 0 and immobiliser seemed to not disengage so I could not start the car. MMM I thought the key fob is low on battery? the key fob aint working or communicating with the reciever? After numerous attempts of trying to reset the immobiliser with the key code and failng I ended up calling the RAC (free on my insurance). After numerous checks it solved.... A bad earth connection to the starter motor. New end spade and job done!