"Don't mess with the design." The message from existing owners was clear when Chrysler came to look at revising their iconic PT Cruiser. Yet pandering to the wants of existing owners wasn't going to get the job done for the Americans in terms of growing PT Cruiser sales. Hence the dilemma you can see in the shape of the latest model.

It's changed - but not too much. So there are new headlamps and a smarter dashboard, Plus more grunt for the diesel version, recognising the importance of that growing part of the market. The petrol 2.4-litre unit continues as before, but then, that wasn't all that old. And prices haven't changed much either, starting from £12,995 across a Range that includes Classic, Touring, 'SunsetBoulevard' and Limited models, as well as an unusual Cabrio model.

So for the detail. There are new round front foglamps and revised tail lights as well as a body-coloured spoiler for PT Cruiser anoraks to spot. Inside, you don't need to be an anorak to notice the differences. The cabin has a much more up-market look and feel in comparison to the previous version which quite frankly felt cheap. The dash has larger gauges, rotating airvents, a 'Chrysler signature' analogue clock and a new stereo, mounted higher for easier access. The centre console has a sliding armrest (replacing the previous fiddly seat-mounted armrests), houses a deep storage bin, a powerpoint to charge your mobile 'phone and has two neat, fold-out cup-holders for rear seat passengers. There are new seat trims and fabric choices too to complete what Chrysler hope is an 'individual feel'.

Under the bonnet, as already mentioned, the diesel engine that represents the preferable choice in the Range now develops 150 rather than 119bhp, a massive improvement bringing with it some 221lbft of torque, enough to ensure you no longer have to row the car along with the gearlever. The latest model is quieter too because there's improved sealing around the heating, ventilation and air conditioning, Plus the panels and dashboard apparently absorb more sound.

All this apart, it's pretty much as you were. Go, as many do, for the 143bhp 2.4-litre petrol-engined model and you might expect a unit of this size to be pretty rapid. In actual fact it isn't, though most mini-MPV customers (yes, that's what this car actually is), should be happy enough to see 60mph come and go in 10.3 seconds with a top speed of 121mph posted.

"The PT Cruiser's changed - but not too much."

All PT Cruisers are still sourced from rather humble stock. The old Neon family saloon provides the basic platform for this car - but you wouldn't know that from a glance inside the far more spacious cabin. It's a bit of a shock to climb inside and find that here, things are a lot more conventional - though various efforts have been made to jazz things up a bit. Some of it works - the pool ball-style manual gear knob is a nice touch - but some of it still doesn't. The thin four-spoke steering wheel for example, still feels a bit cheap.

From a practical perspective however - just where you'd expect the car to be at its least impressive - the PT Cruiser is hard to fault. Though there are only two rows of seats, the cabin is extremely well thought out, with no fewer than 26 different interior combinations. For a start, the second row can be removed completely and has rollers to make the task easier (why has no one apart from Chrysler thought of that before?). They split-fold 65/35 and fold flat on the seat cushions when they do so.

Buyers choose from a wide Range if accessories, including a moulded cargo tray for the estate compartment to keep your furry friends from ruining it. Roofboxes and a purpose-designed ski/snowboard carrier are also popular.

The fashion set who like all these extra touches are particularly being targeted with the flagship Cabrio model. Despite our notoriously unpredictable maritime climate, Britain is Europe's biggest convertible market and we buy more soft tops here than the combined markets of Italy and Spain. If the PT Cruiser Convertible can't sell here, it's doomed.

The variant is being promoted on the basis that it offers more room inside than virtually any other soft-top model. "Our engineers wanted to make the PT Cruiser Convertible a convertible that you can actually do things with," says Larry Lyons, VP Small Vehicle Product Team Engineering. "Nine different seat configurations and a pass-through boot opening with enough room to store two golf bags make the car more versatile than its competitors." Golf bags seem to be the new unit of measurement when it comes to boot space. Even Ferraris are now manufactured with boots that can accommodate a golf bag. It's hard to see the PT Cruiser Convertible at your local municipal. It would look happier crawling along a drive-thru lane or parked outside a trendy bar.

The hood is an electrically powered fabric affair and takes all of ten seconds to fold back. You'll need to twist a centre latch and then prang a dash-mounted button to lower the roof and if you really want to neaten things, there's a vinyl tonneau cover that, unlike many of its ilk, is surprisingly easy to fit. It is, however, quite a bulky affair and takes up a good deal of boot room when not in situ. With the roof down and the windows raised, there's precious little buffeting for the front seat occupants, although those taking advantage of the most generous rear legroom in class will get a sound battering from the wind at speeds much above 50mph. The fixed roll over hoop helps to cut wind intrusion at low speed but even that can't do a whole lot when you really press the throttle pedal.

Although some will still find the styling a little contrived, others will continue to rejoice in the PT Cruiser's retro appeal. As a refreshingly different alternative in what is usually a gut-wrenchingly practical sector of the marketplace, this Chrysler's presence continues to be a welcome breath of fresh air.