After a few more bouts of sporadic inactivity, all seems to be well again with the stop-start equipment on the Insignia we’ve been running for the last six months.

But as we part company with our test model, a question still hangs over reliability over the long term.

The clever gadgetry that aids fuel economy by switching the engine off and then bringing it back into action when it’s needed has functioned perfectly for several weeks and has just operated faultlessly during a period of use that has seen the car cover more than 3,000 miles.

However, at least half a dozen periods of hibernation earlier in our test have left the suspicion that the stop-start could decide to stop again at any time.

For all that, the eco version of the top-selling Vauxhall is leaving us on a high note, particularly so with regard to its parsimony at the fuel pumps.

Since the day it arrived with just 200 miles on the clock, the car’s two-litre motor has been a model of smoothness and power. And it has never failed to deliver impressive operating economy.

Occasional tank-to-tank figures of more than 60mpg have shown this version of the Insignia has the potential to offer handsome rewards to drivers with light right feet. Indeed, our overall test average of more than 55mpg reveals an excellent return for such a practical hatchback model.

It’s fair to point out that the bulk of our mileage has been completed at cruising speeds over motorways and major routes, of course. Yet though the minimum of time has been spent negotiating the urban traffic crawl, the fact remains that this is a commendable level of efficiency for a car of this size.

Like its rivals, this car has the space to accommodate five occupants and their luggage and two Continental trips have highlighted the usefulness of a rear deck which offers a huge amount of cargo area when the back seat is folded down.

There’s no shortage of power to handle heavy loads and an unusually high sixth gear ensures progress that’s refined and relaxed as well as economical.

The Insignia has always deserved its place as a fleet favourite and the recipe keeps getting better – even when the stop-start gadgetry goes on strike.