from '94 on up until '2002(i'm not shure about the late cutoff date), they kept that name.The SD's are lower equipped ones than the SE's.SD7 and SE7 means that they have the extra "jump seats" at the back to accomodate 7 people in total, instead of the normal 5 seater SD's and SE's.The equipment basically differs on "convenience packages", as they share the same engine/transmission.They even vary between SD models and SE models themselves, this because when you bought them new you could have them ordered through your dealer to suit you taste according to the equipment/budget you wanted.I was told this last part at a Land Rover dealer, and I don't know how specific is their veracity.I think that might be true though, as I have myself an SE model with no sunroofs and cloth seats instead of leather or duragrain, but loaded with other accesories.Just my 2 cents.
Carlos
Carlos