Land Rover Repair: Start / immobiliser, uk diesel, discovery 2

Question
Hi there,
I`m having a problem with my 96 Discovery 2.5 Diesel. The key fob etc works to unlock the door and also the immobiliser about 90% of the time but occasionally the doors etc all open and the alarm disarms etc but the car won`t start. The key turns and the lights etc come on but the engine is just dead - doesn`t even try to turn over. If i lock and unlock it then sometimes it works perfectly. Sometimes it takes quite a few locks and unlocks etc before it will re-start. Any ideas what might be causing the problem and how i can fix it?
Any help is much appreciated!
Cheers,
Craig.

Answer
It's clear that you have an immobilizer issue, but the UK diesel uses a different system from what we have in the USA.  You're going to need advice from someone in the UK on this, I'm afraid.

Here in the US that system is only accessible through our proprietary LR test system, T4 or Autologic