If you have a Disco l,it will be a less involved task than having them fitted to a Disco ll.For the latter,you will need to add the whole SLS system,change the rear roof headliner panel(don't know the exact name of that part) in ordet to accomodate the head restraints that pull down from inside the roof,besides the seatbelts,rear carpet,and seat center rails.Too involved...I think.
Carlos