I mess about with the pop-out doorhandles; I take photos of the double helping of front-and-back boot space; then I quickly slump into the driver's seat before anyone asks to see the license that I forgot to bring to the test drive.
There's a huge amount of technology in this £98K ultra-spec version, which costs twice as much as the lower-performance base model. It's dizzying at first: a primary split-screen LCD panel in the centre of the dashboard, with a smaller section at the bottom for climate and car controls, plus another LCD dash behind the wheel that replicates some of the same information from the main unit. This includes a small-screen view of the GPS, which you can just about make out through the gap in the steering wheel.
It's a lot to take in, so better to ignore it, at least for now. I push (or rather "click") out of neutral using an implement that would, in a normal British car, have triggered the windscreen wipers. Then I pull out of the parking slot, keen to get out onto the stilted sequence of bus lanes and CCTV cameras that is otherwise known as a London public highway.
The hi-vis men at the gate have their backs to me and don't hear me coming, even when my front bumper is almost nudging against their heels. Window down: "Hello gents, would you mind?" Startled, they clear the way and I press the metal for the first time.
Woah! I find myself apologising to the Tesla representative sitting next to me. "Sorry, I didn't realise it'd be quite so..."
In a fossil fuel car, even a sporty one, it can take a couple of explosions from the transmission before you really feel the horsepower. And by then you're half-way to the local magistrate's court. It's different with the Model S: The accelerative high is legal, clean and delivered in an instant-action pill with no side effects, regardless of how fast or slow you were travelling before you swallowed it.
A silent punch of g-force, then you simply level out when you hit the speed limit and act as if nothing naughty just happened. Once you've completed overtaking, or joined the A-road, all you can hear is tyre noise and your own breathing. It's like abruptly losing your wanted level in Grand Theft Auto.
Aside from the acceleration, the car feels familiar and European. It's a matter of minutes before I'm dangling my elbow out of the window and enjoying a sight-seeing tour of the postmillennial architecture around the A13. I'm told that Britain is over-represented on the team of engineers that designed this vehicle, and I can believe it.
The dash is starting to make sense by now. The upper panel has six different screens to choose from, ranging from media to the Bluetooth phone interface. The lower panel is showing a large view of the map. But then the Tesla rep switches this to a view of the car controls and finally merges the two panels into one big one. A paradise of customization.