I'm in there now and it was such a pain to get to, that I'm going to replace both now for the sake of £150.

Getting the alternator out was the hard bit - I needed to remove the hard EGR pipe running across the front of the engine (obviously not there on the Petrol engines) - once that was out the way, then it was still a tight squeeze out but doable.

Water pump has very slight play in the bearings, so glad I'm doing it now .. should be relatively easy now as I have plenty of room ..

.. but reconditioning the alternator first while I wait for the water pump and thermostat parts - going to use MAHLE which I think is OEM ?