What are they like inside?

The SL’s interior really looks the part, with a petite, leather-topped gear selector, large bullseye air vents and acres of plush leather. It also has truly supportive seats.

With the roof down and the wind deflector and windows up, you’ll sense the world rushing by, but even at motorway speeds not a hint of breeze enters the cockpit.

In the 911, the centre console between the front seats makes the interior feel quite snug, and the sports seats hold you firmly, so backache can set in quite early. What’s more, when the gear stick is pushed forward into the odd-numbered gears, the air conditioning and radio controls are difficult to get at.

Wind blast is well isolated with the deflector in place, though, and the fabric roof is surprisingly effective at blocking out noise.

Much of the dashboard layout and switchgear in the 6 Series Convertible has been lifted from lesser BMWs, but that’s no bad thing because the quality is so good. Entertainment functions are easily accessible through the logical iDrive rotary controller and are displayed on the central monitor.

The 6 Series Convertible also provides plenty of room for four to travel in comfort, but with the roof down there’s quite a bit of wind buffeting. At least the BMW’s boot is big enough to take a couple of suitcases; with the 911 or SL, you'll struggle to accommodate more than a couple of squashy overnight bags.