In the long run, it might be worth considering getting one of the water filters fitted to the house, they have come right down in price. One of our neighbours got it done and they’ve never had lime related problems since with anything!
Did Libby not say she has a filter in her attic? I have a salt filter fitted, i cant praise it enough, we have no lime at all and you use less washing powder and shampoos etc, 1 cap of bubble bath and you’d nearly vanish with the amount of bubbles….. when we havent put salt in i’d use half a bottle and only a few bubbles