Skoda Octavia
1.6tdi is definitely the way to go, slightly better acceleration, better fuel efficiency (I think the new one uses something like 4.4 ltr per 100km), also less emmissions meaning cheaper road tax.
Agree that only you can decide if you want to pay for the extras in the mid range model, I think the base one does not have alloy wheels, which some people think should be standard on all cars. Also, will you get use out of the Air Con or Bluetooth. I dont think I would buy a car now that did not have air con.
For the same reasons you have, better fuel efficiency, emmissions etc., 1.6tdi will be the most popular model and best for trade ins from here on in. Going forward.
Hope this helps.