A COUPLE of miles into the drive I realised the latest offering to come from Ford was humming quietly along the main road - in fourth gear.

If ever you needed a demonstration that the new Fiesta has matured into an even more serious player here it was, with two gears left to go.

At a stroke the best selling car in the UK for the past eight years has turned from cheeky chappie (but loads of fun) into a car that feels bigger and softer and not quite so keen to have a laugh with you.

That certainly applies to the likely biggest seller in the new range, the Zetec trim version with its 100 horsepower engine and - crucially - new six-speed gearbox instead of the previous five.

There's a more sporty, tied-down, ST-Line Fiesta due in the autumn which early signs say has fun factor 50 but it's going to be a relatively small seller, thoroughly outgunned by less expensive versions - and with the Zetec taking more than half the total sales.

So it's good that the Zetec - second up in a Fiesta pecking order stretching from 70 horsepower petrol at £12,715 Style to 120 horsepower diesel, £21,225 Vignale - is such an instant charmer.

More so on the inside than out, you'd have to say. The exterior of the latest Fiesta has grown very modestly (70mm longer, 13mm wider but 20mm lower) and is completely restyled, although you might never guess.

That's as fine a compliment to the outgoing model as you could pay; don't mess with a look that's won thousands of sales. Doesn't do VW any harm with succeeding generations of Golfs, does it?

The result is a car with space to spare in the front - and a near perfect driving position - but just enough room in the rear for a couple of adults and a boot big enough for a family's supermarket shop, but less generous than some of the competition.

Inside is where the attention needed to be paid, with the old car's dashboard looking increasingly like a relic from the past, littered with meanly-sized displays and an excess of tiny buttons.

All gone! Replaced in the modern minimalist fashion by a big iPad-like touchscreen that looks smart but doesn't have a lot to say for itself without a satellite navigation map on display (sat nav is standard on some of the dearer cars, a £300 option on others).

There's more soft touch plastic than previously, lending a gently more upmarket feel to proceedings. With the posh Vignale version you will enjoy the heated leather seats and steering wheel that a mere Zetec trim car can only dream about.

If the all-change interior is a much needed step up, the engine choice is mostly as before, which is no bad thing if you enjoy the willing thrum of a three-cylinder petrol unit.

Gone is the old and mildly asthmatic 1.25 litre engine, with most new Fiestas using versions of the established 1.0 litre EcoBoost three-cylinder unit in differing outputs - 100/125/140 horsepower and with CO2 readings from as low as 97g/km.

The old 1.5 litre diesel engine remains, in two power outputs (85/120 horsepower, from 82g/km), but will take less than one in ten sales.

The new six-speed manual gearbox will feature in the bulk of new Fiestas, which will have five doors too. Ford is sticking with a three-door option in a market increasingly ditching this choice on the grounds that not enough buyers bother these days to make it worthwhile.

The on-paper list price of most cars is an irrelevance these days and that's absolutely the case with the Fiesta, where 85 per cent of private buyers will opt for a personal contract plan (PCP) that provides a Zetec-spec car from £116 a month over three years and with a £5,000 deposit.

That's an increase of £15 a month over the outgoing model but a drive in the new one makes that look a very sensible investment.

Tweaks to the suspension and clearly a lot of work on soundproofing have changed the Fiesta into a car that quietly soaks up bad British road surfaces, only objecting a little to the biggest bumps, and turning into corners with most of the eagerness of old.

Even with fourth gear standing in for sixth some of the time (blame that newfound quietness) the test drive showed 46mpg in a 100 horsepower version, which never felt underpowered.

If a tiny bit of the puppy dog spirit has gone, you have to reckon the payback in refined progress is going to be welcomed by the majority of owners. And there are quicker, firmer ones on the way soon, don't forget.