Why the hell are you asking us on 12oz? We're a bunch of art fags.
At least you had your alternator and battery checked before you started replacing shit.
I was going to say it was a ground..but then I did the rational thing and SEARCHED ON GOOGLE.
In 10 seconds I found this thread:
http://www.landroversonly.com/forums/f40/2000-disco-ii-shuts-off-while-driving-39137/
Straight from the people who live/breath land rover shit.
"Replace your crank sensor."
It even has a video to help you put a new one in!
Sorry to be a dick, but if you gonna drive a semi baller car, you gotta man up.