The td5 would risk shredding the 'box.
It can be done, I fitted a 2.0 turbo rover t series in a mini, there was a lot involved, the td5 is gonna be similar.
You'd have to remove the entire loom, sus out which parts are needed, like all the engine wiring, the injector ecu, the security ecu, central locking ecu, etc etc.
The td5 vehicle has a transponder in the ignition key, what I did with the mini is remove the reader coil from the ignition switch and remove the transponder from the key and tape it to the coil so it was there all the time, and fiited the security ecu and the central locking ecu (you need the locking ecu as it communicates with the security ecu), there are also a bunch of relays that need sorting out, and connecting up to the correct fuses etc.
As you can see theres a whole load of stuff to be done, it can be done if you know your electrics, but its a lot easier to fit a 200 or 300 engine.