It's all over. Has been for about 48 hours, truth be told; I've just been waiting for the official results to tell you exactly how badly our stab at the Silvretta E-Rally finally ended.

Yes, we came last. Sure, the final standings look bad (see above). But mostly, our penalty points deficit came from our catastrophic first day. On the basis of our score on days two and three, we'd have finished in an almost respectable 20th out of 28. Just behind local hero and ex-F1 driver Karl Wendlinger in an electric Mercedes SLS AMG, as it goes.

I'll settle for that. I'll also settle for the Ampera's very decent score in the rally's efficiency test. We finished 13th out of 18 entrants here, beating Volvo's electric C30, a Tesla Roadster Sport and both of Mercedes' A-class E-Cells. Which seems to indicate that plug-in hybrids can be just as energy-efficient as proper battery cars, if you drive 'em properly.

Our best regularity result came on Saturday, in finishing a 3.5-mile climb within 0.14sec of target. That was still only good enough for seventh place on that particular stage, believe it or not.

I'll remember the event most for the incredible feast of old cars. And I have to extend the utmost respect to the drivers of the really old stuff – 9.6-litre Simplex roadsters, 8.0-litre Rolls-Royce Phantoms and pre-war Lagondas and Railtons among them – for making it down some of the route's descents in one piece. These cars have about as much stopping power as an overladen pushbike.

But I'll also remember taking peculiar pleasure in gently descending from great heights in the Ampera, allowing the battery to regenerate all the while, deliberately avoiding accelerating or slowing very hard, and recycling energy that would otherwise have been radiating off our brake discs as heat. You can capture a quarter of a charge in matter of a few miles, coming down a thousand metres or so, and when you level out it feels like totally free mileage – range out of nothing. Nothing's more liberating than that.