I recently Bought 3 Wheel cylinders from Ebay, listed as new old stock in unopened boxes. As I needed to mod the pistons for my use, I dismantled them and was shocked to see corrosion on the inside where the piston has sat. As Land Rover parts are not that popular from your local Factors, they may sit on a shelf for ages, corroding away. So before using them maybe it would be wise to take them apart and have a look.

They have also been known to corrode whilst on a vehicle.

Yes I agree. But you hope by fitting a "New" one It will will be better than the old you have replaced it with! In one of them it would probably have leaked after a few months. It was that bad.