For that mileage we'd suggest a petrol would probably be a better option. Diesels work well for those who regularly cover long journeys, but a diesel isn't going to get up to temperature and regularly regenerate its particulate filter if it's rarely driven for more than 20-25 minutes at a time. A petrol V40 might be a good choice, although it is feeling a little dated now. The latest Hyundai i30 would be in budget and would be an excellent choice, as would a Honda Civic.