The defender axles you have were used from 2003/4 until now, however they will easily bolt into any coil sprung defender shape landrover ( from 1983-now), any range rover from 1968-1992(?) and series 1 discoveries.
The transfer case is an LT230 and is used in more or less the same applications, however only from around 1984 in the range rover. There are a few people in the US using them in offroad race buggies.

