Most of them actually, but the early 4 cylinders (both petrol and diesel) in particular: the SDV6 was used in some of the early vehicles and is apparently the best of the early engine options, but subject to oil starvation and crankshaft failures. Noting that it's the known issues with the SDV6 that are why I'm thinking of selling my D4, and it's apparently the best of the early D5s. Later Ingenium 6 cyclinder may be better than the 4s though.
This report isn't very encouraging, to put it mildly:
Used Land Rover Discovery 5 review - ReDriven
..... the sheer number of reports of more sporadic mechanical, quality and electronic issues is honestly terrifying. It seems that every single element of the Disco [5] can and quite often does have some sort of issue attached to it.
Because of that, we’re sorry but it’s a no, you probably should not buy one, the very long list of potential issues, and the costs to repair them, are just too much risk.
.... as impressive as the Disco [5] is when it behaves, not only does it often rank at the bottom of its respective class, it’s proving to be arguably the very worst Land Rover or even Range Rover in general.
The earliest D5s are currently selling for about the same as the late model D4s, which tells its own story.

