Being a frugal man of simple means I think I spend more time with an eye on our test cars’ fuel consumption than some of my more leaden-footed colleagues. That and having a 36-mile each-way commute.

Actually, the journey is quite an easy one. I’m on the M40 motorway before I’m in third gear of a morning, then it’s the M25. a stretch of the M3 and, finally, a couple of miles of urban crawl before arriving at the office.

I’ve often noticed that I’m able to record noticeably better fuel consumption on the way to work in the morning compared with the evening drive home. To be honest, I’d not given it that much thought. The morning traffic tends to flow more smoothly than that in the evening, so I suppose I’d absently mindedly put it down to that.

However, I recently spent the weekend with Peugeot’s 5008. It featured, among many other things, a readout giving the car’s current altitude above sea level on the LED display. I’m sure this is something that appears on many other cars’ sat-nav/infotainment screens, but for some reason it really caught my eye in the Peugeot.

And so it was one morning that I noticed my house sits at an altitude of 522 feet above sea level (or 159 metres if you’re in France), nestled as it is on a rocky outcrop in the Chilterns. And 36 miles later I again noticed that Autocar’s riverside offices are just 59 feet (18 metres) above sea level.

No wonder fuel consumption is better on my journey to work compared with my journey home; on the return trip not only does the car’s engine have to propel it 36 miles along the horizontal, it also has to winch its one and a half ton mass (or thereabouts) 463 feet up in the air.

Perhaps there’s something in the notion of the ‘two-way average’ after all.