During the winter months the stop-start system on our X1 fitted as part of the EficientDynamics technology was reluctant to work.

The reasons being that it has to wait until the engine has warmed up before it begins to work, and when there is a drain on the battery – such as heating and ventilation systems working hard – it tends to keep the engine running.

The last few weeks have shown the other side of the coin with running the electronic climate control taking precedence over zero emissions idling.

However, it still likes to switch off when it can – for me usually at level crossings – and I often open the windows and turn the ventilation off to discourage it from restarting until I’m ready.

We’ve also seen an improvement in the fuel consumption. The trip computer reading is edging closer to 50mpg since it was last reset, and on many long journeys more than 50mpg has been achieved.

At the six months mark, it won’t be too long before the X1 is returned to BMW, and they tell us demand for the first used models among dealers is strong.

According to CAP a 2009/59 X1 sDrive20d SE would fetch around £18,550 at auction with 10,000 miles on the clock.

That’s a loss of about £6,000, during the first six months/10,000 miles, and the depreciation curve is shallower after that.

CAP Monitor for June 2010 predicts it will retain 26% of its value after four years/80,000 miles.