This is one of those 'how long is a piece of string' questions, and I think you'll get a different answer from each member who replies.

Having said that, here are my opinions!

With that sort of mileage, a diesel engine would make sense, but at that budget, less so. If you are happy with around 40 MPG then most modern petrol cars up to about 1.8 litres would be OK, so it seems daft to recommend diesel when there is more to go wrong.

The old rule of 'buy the best condition you can' applies here more than what make/model, but one thing I would suggest is that you go up one size to Astra/Focus, for more comfort and refinement.

On your list should be the Japanese makes, namely Toyota Auris or Corolla, Honda Civic (find a good previous shape 2001-2005 model). I wouldn't rule out a 1.6 Astra (2004-11) if you like Vauxhalls, but make sure condition is first class and mileage genuine.

Wouldn't it be nice to fill the car only once a week at most? I have been driving a 90,000 mile 5 year old Mazda 3 diesel. 52mpg; over 600 miles to the tank and very comfortable plus a great drive. Yes diesels can fall over, but for your budget you are less likely to have DPF issues as the cars will be too old. Try it, you may be impressed.

At the moment, I own an '02 1.2L corsa ........ I get about 40mpg .......

Blimey! That's less than impressive.

I do 45 miles each way to work in my tuned Saab 9-3 Aero (2litre petrol turbo tuned to 260hp / 360Nm) and driving moderately in motorway traffic at about 70mph I average 38 to 42 (depending on the traffic). If I drive it really gently down the M40 from work (Redditch) to our customer in Oxford I can get 48mpg (cruise control at 65). I generally get about 34 round the lanes even with giving it some "clog".

Maybe a 1.6 or 1.8 Astra would suit. I'd have thought mid 40s would be achievable without turning into a Sunday driver.

I had a succession of Focuses as company cars between 2004 and 2008 (putting them in your budget now at that age). I found the petrols dissapointingly flat and thirsty.