I have a leak under my sink in the kitchen. The water is leaking from the stop valve and therefore we need to switch the water off from outside of the house to replace the stop-valve. The outside water connection that switches the water off is a circular piece of plastic of about 3 inches in diameter with six little prongs coming out of it. This item is too tight to turn by hand and we are therefore unable to switch the water off and replace the stop valve. Please can you advise me if there is a special tool for unscrewing this item and switching the water off, and if so where I can find one.
