Think landrover say 72k or 5 years, but that seems a lot of miles to me!to see if your early 300 has been modded take a look at the lower pulley, it should have shoulders on,if not it hasnt been recalled, but its doubtfull!
Became a defender when the 200tdi was fitted i believe, nope pretty similar to a defender except for the stickers on the side and the engine.series have leaf springs, not coils.