After receiving great advice from the rest of you rover nuts, I wanted to give back to any noobs out there like me. I just scored a set of rear jump seats for my 1997 Land Rover Disco I and wanted to post the install.

What you should buy:
Two rear jump seats, belts, brackets, hardware and interior body panel.
ebay is a great place to find a used set or the junk yard.

Tools:
A metric socket set, Torx T#30 bit and screw drive phillips and flat head
Note the torx bit is difficult to position on the lower brackets if it is to long you can see it in the picture. You may be tempted to use Channel locks:

My Rover did not come with jump seats from the factory.
Step one: remove Trim piece and locate mounting holes. Seat belt mounts were coverd in tape and bracket mount holes had plastic inserts.



Step two: Install 4 Brackets two high and two low.

Make sure you align the seat belt bolts before tightening the rest of the bracket
.
Step three: Attach seat belts and re-install the trim pieces. thread the seat belt through the trim then put the trim in place. Take care not to destroy the plastic trim holders on removal you will need them again.

Step four: Fit bottom ,then top seat brackets in place. Torx Bit #30 required.
Note: You cant see it here but on the right side clearance is minimal.
My Torx socket was only an inch long but would not.


Now the top bracket,:
I had to cut a hole in the plastic trim to make room for the mounting bracket


Now enjoy your handy work and finally realize the Brits designed the high roof so your jump seat passenger could actually fit.
Cheers