Just letting folks know the new instrument cluster cured the problem. The accelerator is now functioning normally.

When i took the instrument cluster out, i found two resisters were looking a bit scorched around the circuit board.
The price for the cluster was £102 + vat. ( that is the price for a vehicle with-out ABS)

Hope this helps cut the diagnostic time down for the next person.

Thanks to the guys for their comments.

Just thought i'd leave a message regarding the "no acceleration" Fault. had another TD5 Defender in the dealership with the same problem. This time the fault was caused by the wiring loom being chaffed down by the transfer box.

When you look underneath, follow the main wiring loom as it goes by the transfer box, it had rubbed through on the left hand side between the body and box.

Hope this helps a few.

P.S
this vehicle would occasionally lose the use of the accelerator.