We moved into our new house just under 2 years ago and the house was 8 months old. The seller was offering me the water softener then for 800 quid to which I said no because I was perry nieve to their benefits. I was not expecting him to remove the unit but he did. That did leave all the plumbing in place under the sink for me to fit one if I chose too.
Within a week of moving in I was asking the mrs why our brand new kettle is white over inside. I then realised why we needed the softener. Checked local hardness rating and we were very high up.
We ended up buying a Twintec S3 which is the model which Harvey's rebrand. I installed it myself and buy the block salt in annual purchases.
Recently fitted a tri flow tap, like others in here, to allow for "hard" water for drinking.
Brilliant investment albeit not cheap.