As you have found out these fittings come in different lengths, thats possibly because there’s 3 change points with these exhaust fittings for the Tdi.
You should have 3 of these items fitted, if so take one off as a pattern or take some...
That's not a dedicated Discovery 1 rubber hanger for sure so you'll have to find some similar generic one if the original type are not good which means that maybe the exhaust was replaced too