I would recommend a 6 month old approved car from a dealership. You will get it much cheaper than buying it brand new, still a few years left of warranty and make sure to get a car that has low maintenance cost from dealership itself. Buying a full option car is much easier to sell afterwards, than a car with no or little options. Haggle with the prices. If you're gonna drive loads, get a diesel imo and don't go for long service interval oils, they are bad. If the car has auto start stop, stay away from it, the starter goes bad much quicker.
Keep in note where you are going to park it, own driveway / underground parking or on the street? How's the parking at the workplace? If it's tight, a hatchback is worth it.
Buying german cars, get ready for overpriced service
See you chose a Ford Fiesta, it's a great car!
Regarding insurance, check the insurance rates near you ( Postcode ), some areas tend to have higher insurance rates due to car related crime, accidents and other insurancebumpinguppricesduetoscams.
If you have a great insurance record in Pakistan, why not ask them to issue you a nice letter which you can present to the insurance co in the uk? Could help:)
Another trick is call different providers, if the first one gives you a ?50 per month offer, call the next one and say you got an offer for ?40 from the previous once, keep doing it till you reach the lowest price! My friend did that when getting loan for his house