The mains stopcock in the photo which is under a sink cupboard is very hard to turn off, I could not turn water fully off to examine a tap valve in the kitchen, it was in the house new nearby 27 yrs ago. Advancing in yrs I have not got the grip I used to have and my wife cannot turn it at all due to nerve damage in right arm. Could a plumber fit a quarter turn valve, the ones with the red handle? Also if they can are they available with the different size openings? How hard are they to fit on a plastic inlet pipe? Also if able to fit can the valve be half open as th
e current one supplies enough pressure on a quarter turn of the tap handle?