I have just got an ice making machine (Whirlpool K20)

Now, I am unsure if I should use water directly from the mains, water from
my water softener (the type that uses salt) or filtered water in the unit.

I live in quite a hard water area (Orpington, Kent)

Using soft water will obviously stop the machine getting scaled up, however,
I didn't think it was good to drink soft water (we don't)

using filtered water will remove any nasties in the water, but I don't think
it will stop the scale

using soft, filtered, or filtered soft water would be impractical, as it
would mean I would have to re-plumb things! (Although, if soft, then
filtered is the way to go, I could get another filter for the ice machine I
suppose.)

Thanks for any advice!

Sparks...