Based on the above figures, you average monthly run is 1426 KM (plus or minus) and probably higher than that going forward. I would recommend you to go for Diesel, if you have plans to keep the new car for more than 5 years. In that case, the extra amount paid for diesel can be justified. Whether it is a hatch or sedan, it is your call. I personally prefer hatch because of the city factors, parking and usability.