Okay, before you do anything else, take the keys and hide them so nobody can drive the car. If the rear wheels are randomly locking at any speed, you have a major safety issue on your hands and the car should be towed back to the dealership from which you bought it.

The cause of this could be anything from a faulty wheel bearing, a park-brake with a mind of its own or a problem in the transmission, suspension or braking system. But what ever it is, the car can not be driven anywhere in the interests of your and everybody else’s safety.

I would be talking to MG’s Australian customer service department to arrange for it to pick the car up and either sort it out under warranty or replace the vehicle. MG also needs to figure out whether this is a one-off problem, or something that might be a problem in other examples of this model. At which point, a safety recall may even be required.

This model MG is designed and set-up to run as an EV for as much of the time as possible. That’s how it saves fuel and keeps running costs and tailpipe emissions as low as possible. To do that, the petrol engine mainly works to keep the battery charged, rather than actually drive the car’s wheels (which it can, but only in limited situations).

So, what you’re probably experiencing is the engine whirring away independently of the car’s actual road speed, as it attempts to keep the battery charged while going up a hill where the energy required is greatest.

ZS pros include cheap pricing, an easy driving experience and a comparatively spacious interior compared to other direct rivals like a Mazda CX-3. The dash is pleasant, there is a decent amount of equipment and the controls are all simple to use. It should also be fairly inexpensive to run and service, though earlier ZSs like yours require six-monthly rather than 12-monthly service intervals.

There are two engine options - a 1.5-litre four-cylinder model with a four-speed auto on the base Excite, or a 1.0-litre turbo three-cylinder version on higher-specification Excite Plus and Essence grades with a six-speed auto. Note that the latter powertrain is more expensive to service.

Plus, there's still a fair chunk of the manufacturer's warranty left, which is seven years, while capped-price servicing is also offered.

But the ZS does not offer AEB Autonomous Emergency Braking, so only rates a four-star ANCAP crash-test rating.

Additionally, the ZS's suspension is on the firm side in terms of dealing with road bumps, which might upset some occupants, yet there is not much of the 'fun factor' in regards to steering and handling finesse that rivals like the CX-3, Suzuki Vitara, Honda HR-V, Hyundai Venue, Holden Trax, Ford EcoSport and Hyundai Kona offer in spades.

We've also heard complaints about the interior's perceived quality being sub-par, cabin storage isn't generous and Android Auto isn't supported (though Apple CarPlay is).

Finally, the ZS' resale value trails all of the aforementioned competitors by a significant margin, meaning it's on track to be worth less when the time comes to on-sell it.