I'm amazed at you getting 47mpg from an 1800 petrol Zafira. The last 1800 Astra I ran anywhere struggled to hit 35mpg driven gently, in fact the chap I sold it to has complained about its thirst ever since despite doing next to no mileage. If you can get 12mpg more from a heavier less aerodynamic car then you're an economy wizard indeed.

As for a replacement, well BMW don't have a great reputation particularly the diesels in regard to longevity. They suffer from loads of issues as they age. They are good on fuel and have plenty of performance plus you have the prestige of that BMW badge if it so appeals.

I guess it all comes down to your budget and your attitude to car maintenance. If you accept that servicing and repair costs will be high and you intend on using the main dealer to maintain it then it'll probably serve you well but if you plan to scrimp and use aftermarket parts and non-franchised workshops none of which have any clue how to maintain a complex diesel executive like this then you'll suffer major and costly problems.

If I were shopping with your prerequisites and budget I'd be looking at the more modest but much more robust Honda Civic 1.6 DTEC which has plenty of interior space and few vices or perhaps a Seat Leon 1.4,TSi, Skoda Octavia/Superb 1.4 TSi, Audi A3 1.4 TSi or Mazda 3/6 2.0 petrol skyactiv. All of which should if properly maintained offer more value and better reliability.

I agree - no way can a car of that size and shape with a 1.8 NA petrol engine achieve a real 47mpg (even if only one person on board) - probably them reading a none-too-accurate trip computer or getting their sums wrong.

Looks like another 'copy 'n' paste' job for your comments SLO, yet another aspiring BMW owner who probably can't afford to run one properly. Maybe you should just have 'standard comments' in other threads/posts that you just link them to?

Thanks for the replies

well i am amazed too how come a 1.8 petrol gives me such an average but I dont have any computers in the car as it is a zafira, i just put in 50 liters of fuel and go for 500 miles give or take depending on how much local mileage i have done, my usual route is motorway almost always and i drive alone most of the times, my office as per google maps is 35 miles one way and I see it is taking the right mileage.

I only plan to use the car for 3 years as i am already buying 4 to 5 year old car and with 40k mileage on it and i will add another 60k in 3 years and once its over 100k i wouldnt keep it longer.

47 would be quite a feat, given the manufacturer's data (EU test, which is normally an over estimate to variying degrees) quotes a maximum of 49mpg for 'extra urban' driving, 30 urban and 39 combined.

I get more (41-42) than the 'combined' mpg figure (38-39) in my 2005 Mazda3 1.6 petrol [mk 1, not the mk1.5 figures on the car-by-car section] with a similar type of driving pattern and generally being light-footed, but not that near the 48-49mpg for the 'extra urban' figures. I would be (pleasantly) surprised if you could get 500 miles out of it on average over the year - maybe in warm (though not enough to need the A/C on - using fuel to power it) dry weather (I've managed 46-47mpg in that sort of weather, but only mid 30s and 380 miles out of a tank [with a reasonable buffer left over] at best in winter).

Anyway, best to go with the good advice from SLO76 and Avant - your 20k miles a year would normally be on the cusp of the changeover from petrol to diesel engined cars, but given you've indicated most of your journeys will be on fast-moving roads, then looking at some diesels (those that are more reliable as well as comfortable and value for money [but still visually appealing]) may be worth a look. Just avoid the Ford-PSA 'diesel-of-doom' (1.6) in them and Volvos and Mazdas; not sure about the larger variants - best to review cars here that have those 2 and 2.2 ltr diesel engines in them (car-by-car reviews section) and look at other threads on the forum. I know the Mazda 2.2D doesn't exactly have the best rep, however I still think a lot of reliability problems associated with diesels come about when owners primarily use them for short runs - those doing so for regular longer trips on fast-flowing roads seem to have far fewer problems.

The problem you'll find looking at used diesels in particular is that you can't always tell if the car has been used for short trips a lot, even if the mileage is low (this could easily have been due it being driven less often but on longer trips, giving the car a chance to fully warm up and burn off all the nasty soot etc from the system). The VAG 1.4 (140 or particularly 150 ACT) TSi/TFSi petrol would probably do nicely as much as those others listed by SLO and Avant if you want economy and a decent amount of pace.

£12k should get you a respectable one and, yes, it is possible you may get a bill but doing that sort of mileage you are going to put wear and tear on any car.

Personally, I'd go for the auto as (as per above) the 8-speed is if anything more econmical than the manual and a lot more relaxing. I'd go for SE spec and sensible sized wheels too for the sort of use you are going to put it to.

As others have said, it won't do 80mpg but should do 60mpg.

For mainly motorway journeys, a manual gearbox will be better; better economy, better performance and easier to maintain, at least in general. Good luck getting 70mpg out of a 320d mind you; you'd have to drive like a cardinal carrying the Pope.

The 3 series has a ZF 8 speed box which is incredibly efficient on motorways. I had a 530d touring a few weeks ago as a loan car, which has the same gearbox. 75mph on the cruise control, roughly 1500rpm in 8th, and it returned a real 55mpg.

In comparison, my 325d (still a 2.0 engine, confusingly) with a manual gearbox sits at about 2100 rpm at 75mph in 6th. Even on a run up to Glasgow from North Wales I don't see better than 50mpg, unless I'm driving really carefully.