First of all, the decision to buy a petrol or diesel car will depend on how many miles you cover and the kind of journeys you do. If most of your journeys are short or around town, petrol makes the most sense. If you're a high-mileage driver, covering lots of motorway journeys, a diesel is the choice for you. Diesels used for lots of short journeys can be problematic, as you may have found with your Passat.

Unless you cover really high miles, it probably makes sense to look towards a petrol car as they're likely to require less maintenance than a second-hand diesel.

The next decision is the kind of automatic gearbox you want. Torque converters are what most people describe as a traditional automatic gearbox. They're a good choice, and are usually more reliable than complicated dual-clutch systems (e.g. Volkswagen's DSG gearbox). Alternatively, a CVT gearbox (as used in the Honda Jazz) is criticised by some as it can be noisy during fast acceleration, but it's generally very reliable.

Unfortunately, there may have to be some flexibility in your requirements as I'm not sure there's a car that ticks all your boxes for less than £7000. A Honda Jazz would be a good choice, but you'll struggle to find one newer than 2013 with your budget. You could also look at a Hyundai i30 or Kia C'eed - two very similar cars, representing excellent value for money and similar to the Civic in size.