The Alternator on the TDV8 isn't water cooled, I changed one on Saturday. Not a nice job, throw away the 2 hrs book time. you have to take so much off, coolant drain, top hoses, intercooler hoses, top fan shroud, fan, belt, lower covers, coolant pipes in front of it, turbo plastic pipe (which has a habit of breaking)in front of it, then remove the starter cable, then pull alternator forward to just get in to release cables in situ, accessible by unbolting & removing the expansion bottle. You can't get to test them at all as they are blocked by a big steel mounting bracket.
If it's the first one you have done, allow the morning!!

HTH
Regards
Steve