http://www.ebay.co.uk/itm/Landrover-Dis ... 2ed99b8458
These are the ones I used, and have been good since.
In terms out how to remove the locking mechanism its a case of following a Haynes manual if you have one.
If not remove the interior trim panel on the doors, and then there are some bolts and a screw that hold the locks in place (Front windows you will have to undo the bolt that hold the window frame as it needs to be raised about six inches or so).
Once the bolts are undone, simple disconnect all the rods within the door to the lock, take note of what goes where and how it connects - picture are good.
Once the lock is removed, there maybe some bits of the the old spring left, if so remove and take note of how it looks. Fitting the spring is one of those tasks that is not easy to begin with, but once the first one is done its quite straight forward after, I find a small flat screwdriver helps in the pushing the spring lugs into the correct slots.
Let me know if that makes sense.