If well maintained (I mean more frequent oil changes than the book suggests), then the engine should be ok. The bottom end bearings are very long lived, easily capable of 300k providing they have good clean lubricant.
The weakest part of these engines is the valve train, particularly the valve stem tips. These are known to wear at an alarming rate, being detected at as little as 20k. However as hydraulic tappets are used, valve wear isn't really noticed in performance, but it does become noisy with age.
At 200k, I'd expect it to have had a new turbo, which generally last about 150k, and probably a couple of throttle bodies, and probably an EGR valve too.
The drive train will have suffered, as LR don't put crucial fluid changes in the service schedule until 150k, so it's likely already had a rear diff or two (listen for diff noise) and probably a PTU too. Hopefully the gearbox has had a couple of fluid changes over its life, or the box will be worn out.
The rear shocks generally start leaking at around 120k, the fronts last a bit longer, but anything over 130k on original shocks will cause a soft ride, even if the seals are holding out.
People don't seem to bother changing brake friction components any more, so expect to see them in bad condition, and don't be surprised to find sticking calipers.
At 200k the driver's seat will be showing wear to the outer seat cover, and there will be wear on controls like the pedal rubbers and steering wheel.
Go with your gut, it might be in good condition with impeccable maintenance, in which case it could be a good vehicle at the right price.
Mine has just passed the 130k mark, and still drives perfectly with original front shocks and steering rack, but mine did spend a lot of its early years on the motorway, which is easy on vehicle suspension/ suspension compared to pounding up n down B roads.
