My companion's opinion inclined towards incredulity when she discovered that the car she was sitting in cost £20,290. Even the realisation that around 10% of this was accounted for by optional extras did nothing to make her revise her initial assessment, summed up in the phrase, "How much?" Given that those extras included reach adjustment for the steering wheel - £110 for something I'd have thought should have been available as standard - I couldn't help agreeing with her.Her view of the A 180 had in any case been coloured at an early stage. I've sat in other A-Class models before, but she hadn't, and she was therefore unprepared for the effect of the twin-floor arrangement. This is the same in the new A-Class as it was in the old, but familiarity has made it seem no less clever than it did right from the start. The essence of it is that if someone has the bad taste to have a head-on shunt with you, the engine and gearbox will slide underneath your seat rather than (as might be the case in almost any other car of this size) turning your lower portions to mince.An excellent and laudable thing. I would have it no other way. But it does mean that a car which looks like an MPV from the outside feels more like a coupé from the inside. The headroom situation is very good, but not quite as very good as you might think it's going to be. Or as my companion thought it was going to be.First time in, she bumped her head on the top of the door opening, and was still in a bad mood about this at the end of the trip when she got out, forgot that the interior is higher than it seems, and fell to earth like a stone. Soothing words were required, along with an assurance that the A-Class would be replaced by something else in a matter of days.I had mixed feelings about that myself. There were times during this test when I needed to carry a lot of stuff, and the car was fully up to the task - luggage capacity is 435 litres with the rear seats in place and 1995 litres with them folded. You can do the folding only when the front seats are slightly further forward than I like them, but that wasn't a major problem, and in fact under normal conditions there is actually more available legroom than I was able to use.This is quite something, since at six foot three I almost always have to use the full extent of seat travel. To be unable to do this in a "small" car is a spectacularly rare event.I was even more pleased with the behaviour of the turbo diesel engine, whose capacity (despite the implication of the test car's title) is only 9cc away from a full two litres. Performance is as good as it needs to be, and while I didn't achieve the official combined economy figure of 54.3mpg I was happy with an average in the high 40s.The diesel unit is flexible enough - as indeed it should be - to need nothing lower than fifth of the six transmission ratios in most A-road conditions. I wouldn't have wanted to do much gear-shuffling, since the shift quality is nothing special. The location of reverse seemed odd, too. It's next to second, and can be reached only by lifting the lever over a detent.Re-reading that description, I can see that there's nothing about it to suggest any kind of cussedness, but I always found selecting reverse to be an awkward manoeuvre. It's also one you wouldn't want to get wrong, since the car will pull away from rest in second without much fuss, and you can imagine how embarrassing that might be if you were expecting to go backwards.I could live with all of this. I will not, however, be persuaded to spend money on an A 180 CDI until Mercedes-Benz sorts out the ride. Yes, this is a relatively short car, with a significant proportion of its weight a long way above the road surface and a fairly heavy engine under the bonnet. Tricky.But Mercedes has been in this business since before the Great War. It must know how to sort out suspension issues by this time. There is no need for the front end of any A-Class to wallow and heave as if it were being sailed from Hull to Zeebrugge.According to tradition, I should now mention that UK roads are generally much worse than German ones, and that allowances have to be made. Not this time. Even on smooth tarmac, and at moderate speeds, the nose moved around too freely for comfort, and made the car feel more like a full-sized, badly-sorted MPV rather than the compact family car it's meant to be. This is the worst aspect of the A 180 CDI, and one that needs to be addressed quickly. Engine 1991cc, 4 cylinders Power 109bhp Transmission 6-speed manual Fuel/CO2 54.3mpg / 137g/km Acceleration 0-62mph: 10.8 seconds Top speed 115mph Price £18,310 Details correct at publication date