I have a 96 D1 300tdi, and a 98 Prado 3.4V6 Petrol.
The slow noisy 300tdi can be band aid fixed in most situations, just carry basic spares and tool kit. It is pretty economical.
The prado is bigger, nicer and a lot more comfortable, but petrol is very thirsty. (I know you are after diesel.) It is also very capable off road.
The D1 has a pretty tiny useless boot. The prado is a full 30cm, (1 foot) deeper than the disco. The D2 has an extra 10cm over the D1. My disco pretty much has to have roof racks to equal the rear space in the prado.
Both cars have been pretty reliable. Over there especially I would go for a basic no frills, no electronics 4WD.

