Hi Les,
Yes, the gearboxes are all CVT, but have an overdrive gear which changes ratio at about 60mph (the function that the failing pump controls). So its a CVT with a 2 speed auto.
You are correct; if the pump fails, then the car runs in petrol only mode, but with some limitations. On hill starts, the car will be very slow to accelerate, as there is no electric power. The car will not go above 80mph as it is at the top of its variable ratio, without the overdrive gear. MPG is reduced by approximately 20%. Some people have experienced the car limiting its speed, by gradually reducing the limit (my car never experienced this). Overall, its good enough to get you home and to garage to repair the pump bearings. I actually drove for about 5000 miles with a faulty pump.
A horse might sound like a good idea, but the cost of my wife's horses confirms that cars are definately the cheaper option!!!
Giles.