Hi Charlie,
I had a Sedici Diesel, and was more than pleased with it. There is a huge difference in fuel consumption between diesel and petrol. My 1.9 could achieve 52 m.p.g., and I believe petrol owners struggle to get mid 30's. The diesel revs at 33 m.p.h. per 1000 revs, and a replacement timing chain costs £300 inclusive of fitting. The diesel has 6 gears, and it is notorious for being notchy. Road testing may well put you off buying, but I can assure you they all suffer from the same problem which makes it almost impossible to engage 2 nd. gear when the engine is cold. The problem goes away within two minutes of moving off.
The four wheel drive system allows you to choose between 2 w.d. automatic 2wd/4wd dependant on conditions, or lock in 4 w.d. It is advisable not to use lock 4 w.d. unless you are stuck in snow, at 37 m.p.h. this anyway will revert to auto. If you fit snow tyres you will never get stuck, and may well pass a few Land Rovers struggling during your journey.
I have owned the following 4 w d, over the years. Subaru Justy, Renault RX4, Nissan X Trail , Toyota Rav. Landrover Discovery, Freelander. The Freelander was the greatest car I have ever owned, but you cannot get a good used one for much under £20k. The Sedici matches the Freelander in its winter ability, and is light years better than all the others.
Identical to the Sedici is the Suzuki SX4 , the old version. This is still being built in 2 wheel drive mode, the 4 w d ones ceased earlier this year. You may find it easier to find one of these, but as I said before make sure you get the 4 w d model.
Good luck, John.