Hi Shroppielass. The hub motor bikes like the Wisper are not as able on the very steepest hills as the bikes that use the Panasonic motor unit which drives through the gears.
However, if the hub motor is fairly powerful, quite steep hills are handled without any trouble, and the Wisper 705 one is at least mid powered and probably on the high side.
In your case where you are still able to climb the hills on an MTB, albeit with a struggle, you should find them easy enough on the Wisper, climbing them at a higher speed and impressing the natives.
I've had a look at your area on Google Map in 3D view and the hills shouldn't trouble the Wisper, even the roads and lanes over the large hill to the east of Great Lyth wouldn't be a problem if you got down that way.
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