Before you start looking at the vehicle:
Make sure it has 2 keys and fobs. Replacements are expensive, so any missing keys or fobs can be negotiated off the price.
Tyres:
Make sure it's got 4 identical tyres. It looks like the tyres front to back are different, which will trash the AWD system in time.
Have 4 matching tyres fitted asap.
AWD system:
Make sure the propshafts are fitted. If not, then assume the IRD (the Freelander's transfer box) is goosed, as that's normally why the props are removed (it's not for fuel economy, which is the normal reason given). Also check for clunks and bangs from the underside when changing gear, as that can often be rear diff mounts failed.
Engine:
Make sure the engine starts quickly and runs smoothly from cold. Mine starts on the button, even if it's not been started for weeks. Look at the engine for oil leaks and lack of maintenance, as these engines are from BMW, so regular maintenance is needed. The crankcase vent/separator is often neglected even though it costs a couple of quid. This then causes pressure in the crankcase, causing oil leaks from the dipstick and cam cover.
The high pressure fuel pump can leak too, so make sure that's dry.
Gearbox:
If it's a manual, make sure the clutch is light to operate, and the biting point is about 1/2 up the pedal movement. If it's near the floor, then suspect an issue with the hydraulics which will need rectification. Also if a clutch hasn't been done in the last 60K miles, budget for a replacement soon.
If it's an automatic, make sure it changes gears smoothly, you should hardly feel the changes going up the box, although down changes can be felt on occasion on the TD4. Check to see when the fluid was last changed, and have it done as a matter of urgency if it's not been done.
Make sure stuff works:
It's an SE, so make sure everything that makes it an SE is working. It'll have heated front seats, which should warm up and not be to damaged, as correct SE replacements are hard to find.
Make sure the power fold mirrors work too, replacements are expensive.
It could also have a heated front screen (can't do without mine), so if it does, make sure that works too.
Make sure the AC is working, check for the AC clutch clicking in and out, which is audible from the front of the engine.
Dashboard:
Make sure there are no warning lights on the dash, once the engine is running, but make sure all the warning lights come on then go out. It's not unheard of for lights to be covered up or broken to hide issues, rather than fix them.
General condition:
Make sure all windows work up and down (including the tail door window) and doors all lock and unlock on command.
Make sure the under boot floor cubby box is dry, as they often fill with water from a couple of places.
Make sure the vehicle looks like it's been looked after.
It seem a reasonable price, as long as it's not got many issues.
For reference, I paid £2K for my 05 TD4 SE auto 3 years ago, with 99K on the clock.