Great Quality & flexible arrangement

This comes as a bag of parts which at first seems a bit unnecessary, but what it does allow is great flexibility on the layout of how you assemble it. There are numerous ways to do it and it means you can accommodate pretty much any arrangement required to fit your space/layout.
It seems expensive just for some valves and hoses when you look at it on the website, but as another feedback mentions, they are very good quality and are indeed, full bore devices (ie; they don't restrict the flow by narrowing the bore like most you see in DIY shops). It also comes with a non-return valve for the supply leg which does look like it ought to restrict flow, but it doesn't seem to be noticeable. I have to say though, unlike another review the hoses I received do seem to have a restricted bore a bit in the steel end parts, so maybe the model of these has changed.
Regarding installation; make sure you tighten the compression fittings very well when assembling the arrangement. All parts are steel or brass so are not as malleable as copper, so need an extra "nip" (even then, I had a couple weeping after a day until I nipped them up even more).
I replaced the original incoming isolating tap to the house by adding a couple of elbows to the pipe ends once it was removed and plumbed up to the bypass arrangement (which is mounted on the back wall of the cupboard under the sink). I can now easily isolate the house by closing the inlet valve and the bypass valve which are just quarter-turn valves.

15mm / 22mm Water filter and Water Softener fitting plumbing kit

I ordered the 15mm version and although the kit has not been fitted yet it looks great. The fittings look good quality and are full bore as described. The hoses are better quality than the usual washing machine type and are full bore too. Another good thing is with this kit you end up with 6 compression joints instead of the usual 10 when using conventional fittings, so less chance of leaks. Very pleased with my purchase.