Some things should never be mixed together, such as a Mars Bar and batter, and fat women and wet T-shirts.

Here’s another one for you: teenage boys, paintball and white leather interiors.

Yet here I was, sitting in the glamorous new Lexus IS 250C with my 13-year-old son at arm’s length, looking bedraggled and bruised after a day in the killing fields of Delta Force, somewhere in Yorkshire.

The leather seating was in off-white, he was every paint-spattered colour of the proverbial rainbow.

But with the aid of a black bin-liner and the threat of no pocket money until the world came to an end, the IS 250’s interior remained spotless.

The new Lexus model’s instant and seemingly universal visual appeal is a far cry from the divisive convertible model that predates it. The SC 430 was distinctive, but far from suited to all tastes. At more than £50,000 and with a V8 engine, its price and running costs made it even more exclusive.

Not so the IS 250C. Granted, Lexus is not giving the model away, but with prices starting at less than £35,000 it’s a considerably more accessible vehicle and a rival to the BMW 3 Series Convertible or Audi A5 Cabriolet.

Unsurprisingly, Lexus expects the new model to attract a younger audience, albeit one that’s still mature by most standards. Mature enough to appreciate the highly impressive levels of refinement inside the cabin. As is the norm with Lexus models, the engine is a hushed affair at start up and tick over, with only a slight increase in volume as the revs rise.

The engine itself is a 2.5-litre V6 unit with more than 200bhp and a reasonable degree of torque. Performance is relatively sedate however, despite Lexus’s best efforts to keep weight down with an aluminium roof, but the super-smooth way that it gets up to speed makes up for a lack of punch.

The six-speed automatic gearbox makes the changes near- unperceivable and reacts well to differing driving styles, shifting through the gears quickly and seamlessly at low speed and helping to achieve the respectable 30-plus mpg figure.

A discreetly positioned switch allows the driver to switch from “normal” to “power” mode (there’s a third option for snow, too), which makes the experience a little livelier by allowing kick-down – greatly appreciated on an uphill stretch. Of course, all of this can be over-ridden using the standard-issue paddles to change gear. The response is quick, but the changes remain very smooth.

The same applies to the handling. The steering is the most notable aspect, responsive and nicely weighted. The model corners with agility but doesn’t feel sharp or twitchy, refusing to let the rear get out of shape but without succumbing to debilitating under-steer. It’s clearly been tailored for comfort rather than sportiness.

That’s a decision that’s paid off, because the emphasis on comfort means the IS 250C offers the same relaxing experience roof up or down. Quick to fold, quiet and graceful to watch, it’s a smart system that leaves just enough room in the boot for the essential golf bag when dropped.

With the roof in place, there’s a lack of visibility out of the rear, but the absence of B-pillars aids the view over the shoulder. Careful sculpting of the body means that the interior remains calm and buffeting free – even at motorway speed – and comfortable seats combine with the hugely impressive suspension and wobble-free body to make for a class-leading topless experience.

In the rear, there’s enough room for two average-sized adults thanks to arched front seats that allow more legroom. Shoulder space is a little tight, but the large doors make the rear easy to access. In the front there’s more smart design in the shape of the softly-lit instruments and masses of equipment and the prettiest illuminating kick-plates you ever will see.

Drivers looking for a sporting performance from a medium-sized convertible are not short of options, but those seeking a truly refined experience need look no further than Lexus’s drop-top IS.

Fact file

PRICE: £43,250
Engine: 2.5-litre petrol unit developing 205bhp and 186lb/ft of torque
Transmission: 6-speed automatic transmission as standard, driving the rear wheels
Performance: Maximum speed 130mph, 0-62mph 9.0 seconds
Economy: 30.4mpg
CO2 Rating: 219g/km