If you get the car on a suitable and safe bit of road, where you can coast and switch the ignition off, you will see the difference (if there is a difference). Whatever you do though, don't take the key out, or the steering lock will engage.
I tried engine off coasting with my car, and found that at higher speeds there was not a lot of difference, but at low speeds, such as you would use when parking, the steering is horrendously heavy.
Try another Mk 1 Jazz and see how it feels. Search Auto Trader for a nearby trader selling one, and try a test drive. The Jazz power steering is not particularly light, in my experience.