Right, axles are a straight swap, gearbos and transfer box will be OK as well, but the 300TDi is a bit more complex to fit. Also the props might be a bugger to get the right ones to fit. It would be a nice conversion when done, but I would go for a £400 MOT failure Disco and put in engine/box/t-box/axles from that. Straight swap, slightly higher gearing and disks all round.
Rangie 300TDi Soft Dash? Why does he want to break it they're as rare as rocking horse ****, not many of them were made - I'd spend the time and money restoring it...