Land Rover Repair: 2000 4.0 Range Rover wont start, engine management ecu, body control module

Question
About a week ago my car was running fine.  I went and had the car valeted and when I went to pick it up the car won't start.  When you put the key in the ignition it sounds as though it is turning over but won't start.

It got towed to my mechanic who has been looking at the past 3-4 days and says that he can not find anything mechanically wrong with and that it is an electrical problem.

The car recently got a new battery (about 2 months ago), and had the tire rod and the two front u-joints replaced, a tire rotation and an oil change about 3 weeks ago.

Answer
Mainly when a starting trouble given, the fault oftenly the engine must be resyncronise to the body control module. Oftenly when the car wasn't used for long time, and the battery was drained.
So, I think the engine management ecu had lost the syncron with the body control unit. They communicating with a digitally coded channel.
You should go to a LR workshop then they can fix that.