Sorry to butt in on this one but one thing the helpful poster didn't mention was how to bleed the system when the sink is replaced?? Chances are on this system water will not flow from the hot tap when it iaa
s all connected back up because of airlocks.
Ideally if you are fitting a monobloc tap then just hold your hand over the spout and turn on hot and cold taps until the flow reaches back to the header tank.Don't hold on too long to prevent blowing the cylinder.
There is maybe a safer way of doing this but i have never had any problem this way.